The Somfy Factor 2nd Edition UK

The Somfy Factor
2 nd Edition
The impact of dynamic solar and daylight shading
in offices, educational and healthcare buildings
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Talent for transition.
The chameleon.
Extremely sensitive.
Particularly sensitive to light.
In control of change.
Has a 360 degree field of vision.
Capable of controlling its temperature.
And changing colours in a matter of seconds
when necessary.
With this talent for transition in mind Somfy
has designed something incredibly special.
A technique that enables buildings
to do the same.
Allowing them to prepare for light and shade.
Facilitating continuous adaptation
to changing weather.
To create a comfortable indoor climate.
That produces an optimal feeling of comfort
and wellbeing in a sustainable way:
the Somfy Factor.
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CONTENTS
The Somfy Factor (2 nd Edition)
The impact of dynamic solar and daylight shading
in offices, educational and healthcare buildings
Foreword 10
1 Introduction 13
2 Interesting facts about daylight 27
3 Daylight in buildings 47
4 Dynamic solar shading in buildings 53
Offices
5 People in office buildings 63
Optimising productivity in an office environment by controlling the admission of daylight 75
7 Quantifying productivity gains from the use of solar and daylight shading in offices 97
8 Determining the average annual productivity effect in offices 131
9 Translating theory into practice 135
Education
10 Educational architecture 147
11 Avoiding overheating in classrooms 153
12 Model and selection tool 157
13 Reference model: Basic principles and building characteristics 165
14 Temperature overshoot and cooling load calculations 169
Healthcare
15 History and architecture of care buildings 185
16 Indoor environment - parameters 213
17 Literature study 221
Supplement 1: Productivity and sustainability go hand in hand in ecological agriculture 249
Supplement 2: Artisan production of naturally dyed textiles in the Chilean desert 273
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FOREWORD
For years now I have had the idea of setting out the scientific foundation
for the application of solar and daylight shading in non-residential
buildings, more specifically in offices, education and health care
facilities. Back in 2019 I finally bit the bullet and got started on the task.
In early 2020 I came to the conclusion that I'd made the classic
mistake of making the scope of the project far too broad. There were
three options: give up, carry on and run the risk of getting bogged down
somewhere, or split the subject up into smaller projects. Given that I'd
set myself the goal of solving the puzzle completely, the final option was
the obvious choice.
I've divided the project up into different parts, all of which aim to map the
effects of dynamic solar and daylight shading on the indoor environment
in offices, education and health care, as well as the impact of shading on
energy consumption and CO2 emissions.
The order I've chosen is not entirely coincidental. In light of the trend
towards making buildings energy-neutral, ideas about the impact
of dynamic solar and daylight shading on energy consumption in
buildings – both new and existing – are changing. Another point, too,
has been clear to me for a number of years now: the payback period for
the investment required for dynamic solar and daylight shading, when
taking only the energy bill into account, provides insufficient incentive
for investors. New buildings have not been connected to the natural
gas supply for several years now, and solar energy is frequently used
to generate power for things like cooling buildings in summer. These
developments have made it necessary to update the arguments for
dynamic solar shading.
It is in no way my intention to cut out the energy consumption argument;
rather, to emphasise it. When all is said and done, existing buildings hold
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enormous potential. In addition, the extremely high energy prices that exist
today are having a significant effect on the outcomes of the calculations.
Another aspect to be considered is that the post-coronavirus era has
now begun. What must we do in order to motivate staff to return to
the workplace? That is a question of particular importance in the case
of office buildings. The very least that can be provided is an indoor
environment that is as good as it can possibly be.
The second edition of this book has been subdivided into three sections,
each of which focuses on a specific type of building encountered in the
sectors being studied: offices, buildings used for the provision of care
and buildings in which education is provided.
A follow-up to this book is also already fully under way and has advanced
to such a stage that a second, entirely new book will be going to press in
the very near future. A website containing a large amount of information
for decision-makers and influencers is also being prepared. The website
will also give our specifically trained specialists and partners access to
specific tools that have been developed using the knowledge acquired.
This will enable the sector to adopt a more professionalised approach
and to provide decision-makers with more effective support as part of
their decision-making processes.
Sven van Witzenburg
Hoofddorp (NL), March 2022
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1INTRODUCTION
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THE REALISATION OF A BUILDING
This book is about buildings and people; more specifically, office buildings and the people who work
in them. An office building is a building in which employees of an organisation carry out their work.
Typically, people who work there mainly perform their duties while sitting down.
The definition tells us that buildings are constructed in order to house people. They have their
workstations there, meet colleagues, visit clients, receive suppliers, hold meetings there, and eat
their meals there, for example.
An architect (Greek: architektón: master builder;
archi: master or chief, tektón: bouwer) is a designer of
buildings, someone who visualises the design and directs
the realisation of this concept, both technically and
administratively. In the Netherlands there are several
training programmes that enable graduates to qualify
for the Register of Architects, permitting them to use
the title of 'architect':
- Practical (state exam);
- Delft University of Technology or Eindhoven
University of Technology. Graduates hold the
internationally recognised title Master of Science
and the Dutch title of (architectural) engineer;
- Architectural Academies, further education
after graduating from the HTS or Art Academy.
On successful completion of the programme,
graduates have the right to use the (international)
title Master of Architecture.
Alongside the structural aspects, architects are primarily
concerned with the shape and colour of a building – its
appearance – and are keen to leave their mark on it.
Architects tend to specialise in either the exterior or
the interior of a building, and in some cases on the
combination of the two.
An architect usually receives a design commission
from a client. The architect begins by producing a rough
draft with an estimate of the costs. If the client is in
accordance with the design, the architect goes on to
draw up the building plan. After this a public or private
tender can be held. In both of these, the contract is
usually awarded to the applicant with the lowest bid.
The architect may also work with a building contractor
to draw up a quote, a preliminary estimate of the building
project's costs. If this is approved, the project will be
developed further.
A person who has the right to practice as an architect in
one EU country is entitled to do so throughout the EU. In
the Netherlands, only those who are listed in the Register
of Architects are permitted to use the protected title
'architect'. In addition, many architects in the Netherlands
are members of the professional organisation BNA, the
Branchevereniging Nederlandse Architectenbureaus
(Association of Dutch Architectural Bureaus).
The architect is, in principle, responsible for the
programme, building shape, layout, construction, colour
and choice of materials, based on the client's financial,
functional and aesthetic requirements. Following the
linear method, the architect creates a design, then
has it further developed and checked by architectural
consultants. After this process, the contractor
constructs the design.
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Complex installation systems and construction methods,
increasing building size, and the technical integration of
the façade all require external specialists who support
the architect from the design phase onwards.
They work with the architect to complete the design
based on knowledge of their own fields. The application
of knowledge and expertise from various building
disciplines during the design phase helps to prevent
unforeseen costs later on. It also makes it less likely
that problems will arise in the later stages. For example,
the main contractor doesn't sit around waiting for the
architect to serve the project up on a plate; rather, he
or she is already involved in the discussion during the
design phase to help spot potential problems during
construction. This method is known as integral design;
the client and the architect usually head the project
management of this integrated construction team.
The architect is generally tasked with developing a
design vision and a spatial plan, as well as monitoring
the overall quality of the end product by supervising
the specialist construction team (builder, structural
physicist, construction technologist, etc.)
After the initial sketch design, the architect prepares
the scope statement and the associated drawings.
Working drawings and detailed drawings of floor plans,
facades, frames, windows and doors are created by
drafters in the architect's office, or outsourced to a
design & draughting bureau.
These days computer programmes and computer-aided
design (CAD) are used to facilitate technical drawing
and the creation of the design.
Once the drawings are ready and there are technical
calculations in the design, a copy of everything is sent
to a structural engineer who calculates the structural
aspects of a building, such as the span of an arch and
the load-bearing capacity of walls, columns and the like,
or to the building physics consultant who calculates the
thermal, hygric, acoustic, fire safety and energy aspects.
In order to obtain a Dutch construction permit, the
supporting structure must be calculated in accordance
with Dutch building regulations and Eurocodes.
If everything is in order and the client is happy with
the design, the architect writes the scope statement.
The scope statement elaborates on all aspects of
construction in detail and is an important document for
the contractor. For example, it includes the materials to
be used, colours, sizes, and the construction method.
The design needs to be approved not only by the client
and the structural engineer, but also by municipal and
government authorities, such as the building control
department and housing inspectors. In the Netherlands
there are building regulations to be observed, for
example those governing the building's height and
appearance, such as the zoning plan and the regulations
regarding buildings' external appearance. The architect
him- or herself usually conducts these discussions. It
is sometimes necessary to make changes to certain
aspects of the design.
Once the authorities have given their approval, the
contractor can begin construction. The contractor and
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the architect maintain close contact throughout the
construction process, and a committed architect will
make regular visits to the site. This allows him or her to
conduct technical discussions with the foreman, who
supervises the construction work on the architect's
behalf, and possibly also with the site manager, who
represents the contractor and is responsible for the work
carried out on the site.
efficiency, it is advisable that essential issues – which
ultimately determine whether people feel comfortable in
a building – are taken into account at an early stage of
the design process. Taking action during the construction
process, or making changes to the building or its
equipment and fittings after the building is finished,
costs time and money. Omitting essential elements
reduces the building's value or functionality.
If the architect's commission includes the management
of the building project as well, s/he will be responsible
for ensuring that these meetings run smoothly and that
minutes are taken.
People in buildings
In today's society, people spend a large part of their lives
in all kinds of buildings.
When construction is finished, the official completion, or
handover to the client, takes place.
An architect’s fee is usually dependent on the total
building costs, with the architect usually receiving
a certain percentage of these. There are guidelines
surrounding the level of this percentage, but they
no longer have any legal status due to EU anti-trust
regulations.
A typical life:
From birth to age 4 Mainly at home
5 to 18 Home and at schoo l
18 to 23 At home (student accommodation)
and in further education
23 to 67 At home and in a workplace
environment
67 onwards Mainly at home again, and in
many cases in aged care as well
BNA, along with other parties, has drawn up regulations
governing the legal relationship between an architect
and a client. These are known as 'De Nieuwe Regeling'
(DNR 2005). In 2011 an updated version – DNR 2011 –
was published. A revised version, still under the name
DNR 2011, was issued in July 2013.
People commonly work in buildings, as well as meet
colleagues, visit clients, receive suppliers, hold meetings
there, and eat their meals there, for example. In today's
society, people spend a large part of their lives in all
kinds of buildings.
It's important to take a moment to consider the
construction process, and particularly the role played
by the architect. In order to ensure effectiveness and
People in the Western world today easily reach an
average age of over 80 years. They work for more than
half of this period; most of them inside buildings.
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If we look at the typical way that people spend their time during this
life stage, it turns out that apart from around five weeks of holiday per
year, in Western countries the way that the 168 hours of each week are
spent follows generally established patterns. People work around eight
hours a day, sleep for seven to eight hours a day, and the remaining eight
hours are spent on sports/hobbies/commuting/shopping/entertainment
outside the home (around two to three hours a day) and on family/eating
and preparing food/studying and other things inside the home (five to
six hours a day). Weekends have a completely different format, which
usually doesn't include work. Roughly speaking, people work for 40 of
the 168 hours in a week (24%). This means that on a yearly basis, taking
into account five weeks of holiday and 3% sick leave, people spend 20%
of their time at work between the ages of 23 and 67. When measured in
terms of their time on earth people spend more than 60% of their lives
inside buildings.
It is important to consider buildings from that perspective. Obviously
it's a good thing when a building is appealing to look at, and the façade
often says a lot about the building’s users; in fact it is often used to
communicate with the surroundings. Buildings are primarily constructed
in order to house people, so it is not entirely illogical to consider whether
the building is functional and whether people feel at home there. There
is no need for a scientific study to determine that everyone knows, from
their own experience, that people prefer to spend time in spaces they
like. When people feel comfortable they're able to concentrate better,
they feel better, things take less effort, and the return on activities is
therefore higher.
Many things in a building can cause distraction. Distraction usually
arises from sensory perceptions. Sight, hearing, smell and feel have
everything to do with a building's construction and layout. This means
that alongside look and feel, things like light, sound, air quality and air
movement in a building are essential. This book focuses on one of these
aspects, light – more specifically daylight.
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The importance of daylight
The content of this book is a journey of discovery towards
optimising the use of daylight in an office environment.
Daylight enters the building via the façade. Humans must
have daylight in order to function optimally. Sometimes
there is insufficient daylight available and the situation
calls for artificial light, and in other situations there is too
much daylight and it needs to be dimmed. This can be
done in a number of ways, for example through the type
of glass used in window openings, but it can also be done
by using solar or daylight shading, either fixed or movable,
on the windows.
Daylight, or natural light, consists of both the direct light
from the sun and the indirect light that is diffused by the
atmosphere and the clouds before it reaches the earth.
The length of daylight in a 24-hour period depends on the
location's latitude and on the time of year.
Daylight is important to much of life on earth, for human
functioning, and for people's health in general. For this
reason, much research into the effects of daylight on
daily life is conducted by experts from the worlds of
business, medicine, academia and other areas.
Daylight enters buildings through windows, and the
amount and type of light in a space is dependent on
the orientation, position and size of the windows. In
the Netherlands, for a space in a house or an office
to be considered habitable according to the building
regulations, there must be sufficient natural light
available. The standard for this is set down in the
Building Code (NEN 2057). The Building Code states that,
as a rule of thumb, the glass area must consist of a
minimum of 10% of the available floor space.
Having sufficient light enables us to see much better,
but natural daylight has another advantage: it helps
to regulate the circadian rhythm. This biorhythm
determines, among other things, sleeping and eating
patterns, body temperature, performance and mood.
Natural light promotes the proper functioning of the
human body. Studies of natural light consistently show
that good daylight is an important factor in stimulating
our biorhythms. Exposure to sufficient light makes us
feel better during the day and sleep better at night.
The reverse is true too; too little light can adversely
affect this physical process, resulting in health problems,
sleep disorders, stress, concentration disorders, and
malaise or even depression. There's a good reason
why people are more likely to be unhappy in the darker
months of the year and suffer from so-called SAD, or
Seasonal Affective Disorder.
The elderly are particularly affected by insufficient light.
The lenses of their eyes become cloudy, meaning that
less light enters – up to five times less light than in young
people. This can mean that an older employee – otherwise
healthy – may tire more easily due to a lack of light.
In almost every profession, good light is a prerequisite for
being able to work effectively and efficiently. Exposure to
sufficient light allows us to see what we're doing, avoiding
unnecessary accidents. In addition, light appears to be
related to feeling better and fitter. This is particularly true
of the natural daylight produced by the sun.
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People are visually oriented. Without light it is difficult
for us to orient ourselves in space and there is no
feedback on our actions. This means that insufficient
light in the workplace can result in errors and production
loss. In addition, in many industries good light is very
important for safety.
The rotation of the earth means that daylight is
constantly changing in intensity, direction and colour,
which stimulates the biorhythm. Daylight also contains
many different types of radiation, which are important
for vitamin production in the human body.
The positive effects of light are particularly applicable
to natural light. Standard artificial light is less intense
than natural daylight. It is therefore recommended
that employees have as much exposure to daylight as
possible. If there is no way to ensure exposure to natural
daylight in the workplace or if it is insufficient, the best
option is to achieve calm and natural lighting through the
use of artificial light in the form of full-spectrum daylight
lamps combined with high-frequency fixtures.
Employers are responsible for providing good lighting in
the workplace. This is stated in article 6.3 of the Working
Conditions Decree:
- Places of work and connecting roads are lit in
such a way that the available light does not pose a
risk to the health and safety of employees;
- Places of work have sufficient daylight available
– to the extent possible – and adequate artificial
lighting is provided;
- The artificial lighting is installed in such a way as
to remove the risk of accidents;
- The colour of the artificial lighting may not alter or
influence perception of the health and safety signs.
Clearly lawmakers also believe that daylight is the
preferred option. Article 6.4 of the Working Conditions
Decree adds that building users must be able to block
direct sunlight.
The website of the Ministry of Social Affairs and
Employment (www.arbeidsportaal/onderwerpen/licht)
sets out a number of guidelines relating to this issue.
For example, the following measures should be taken to
ensure that workers have sufficient light at work and it
does not cause a hindrance.
- If there are complaints about insufficient light,
place workstations closer to the window. If there
are complaints about reflection and glare caused
by too much daylight, move workstations further
away from the window;
- Orient computer workstations in such a way that
the viewing direction is parallel to the window. This
means that staff are not facing the light (i.e. do
not have faces turned to the window) and daylight
doesn't fall on the screen (if they are seated with
backs to the window);
- When staff work with screens, ensure that
there is suitable solar shading that can block
reflective daylight, for example awnings, blinds
or tinted glass;
- When working at night, consider using daylight
lamps or a dynamic lighting system that is able to
mimic the variations of sunlight;
- When working without much daylight, be sure to
take sufficient breaks.
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The same website gives a number of other important
points in this regard:
- The rotation of the earth means that daylight
constantly changes in intensity, direction and
colour, which stimulates the biorhythm. Daylight
also contains many different types of radiation,
some of which are important for vitamin
production. Another important advantage of
daylight is the contact with the outside world that
it provides;
- Daylight can have disadvantages too. Bright
sunlight can be a nuisance when working on
screens. It creates reflections and makes the
screen harder to read. People who do a lot of work
outdoors should also avoid exposure to too much
daylight. Being exposed to UV rays for too long can
damage the skin.
Comfort and wellbeing
In essence, these issues relate to how people feel when
in a particular building. This leads us to other concepts
that are important in the context of this book: comfort,
wellness and wellbeing.
Comfort is that which is comfortable and pleasant.
In this book, comfort is used to mean feeling at ease,
in relation to facilities, amenities or design.
Wellbeing refers to the degree to which a person feels
good physically, mentally and socially. It therefore
involves feeling good about yourself, as well as being
physically healthy, and happy with your life. A high or low
level of wellbeing can affect how people or employees
function in everyday life.
A feeling of wellbeing is described by some as happiness.
Good wellbeing means that a person is doing well
physically, mentally and socially.
The energy label is a measure of the energy quality of
the built environment. Office buildings with an A label
include many energy-saving measures. But offices with
a G label still have many options for the implementation
of energy-saving measures. The energy label is not
only a measure of energy efficiency; it indirectly says
something about the building's comfort level, the
monthly energy costs (high or low), and the technical
quality. (source: rvo.nl)
This brings us to some other important related points:
energy consumption, CO₂ emissions, and building
certification with relation to these. On 1 January 2023,
every office building that has more than 100m² of office
space – and with the usable area of this office space
being 50% or more of the total surface area – must
have an energy label of C or higher. Buildings that do not
meet these criteria may no longer be used as offices as
of 1 January 2023. By 2030, every office owner will be
obliged to meet the requirements of label A.
This label obligation was agreed in the 2013 Energy
Agreement and reaffirmed in the 2019 Climate
Agreement. The latter agreement states that the
built environment in the Netherlands must be energyneutral
by 2050.
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2
INTERESTING FACTS ABOUT DAYLIGHT
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SUNLIGHT
Sunlight, or – to use the more scientific term – solar radiation, is the main source of energy for the
Earth's climate system. Solar radiation is the source of energy for atmospheric circulation and
the water cycle, and plays an important role in a large number of the climate system's processes.
The amount of solar radiation reaching the Earth's surface – known as global radiation – impacts the
temperature at the Earth's surface as well as evaporation from plants and the soil. Clouds strongly
limit global radiation, and can cause large variations in global radiation within short periods of time.
Cloud cover decreases global radiation by an average of 20%, resulting in a reduction of surface
temperature. However, clouds block the long-wave radiation emitted by the Earth's surface as well.
This has a warming effect. Figure 2.1 gives a schematic representation of the average impact of
these and other effects on the global energy budget. Over long periods of time, the incoming global
radiation at the top of the atmosphere is balanced by the reflection of solar radiation and emission
of long-wave radiation.
Figure 2.1: Earth's energy budget: an estimate
107
Reflected Solar
Radiation
107 Wm -2
Reflected by Clouds
Aerosol and
Atmospheric
Gases
77
342
67
Incoming
Solar
Radiation
342 Wm -2 Emmited by
Atmosphere
Absorbed by
Atmosphere
Emmited by Clouds
165
30
235
40
Atmospheric
Window
Outgoing
Longwave
Radiation
235 Wm -2
Greenhouse
Gases
24
Latent
78 Heat
Reflected by
Surface
30
168
Absorbed by
Surface
24 78
Thermals Evapotranspiration
350
40
324
Back
Radiation
390
Surface
Radiation 324
Absorbed by Surface
Source: Kiehl and Trenberth, 1997: Earth’s Annual Global Energy Budget, Bull. Amer. Meteor. Soc. 78
28
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The sun emits radiation in the form of electromagnetic
waves. This is known as extraterrestrial solar radiation.
This radiation is filtered through the Earth's atmosphere,
arriving at the Earth as global radiation. This global
radiation comprises radiation of wavelengths in the
300 to 3,000 nm range. Radiation of 3,000 to 100,000
nm (3 to 100 µm) is not emitted directly by the sun; it is
heat radiation. Table 2.1 gives an overview of the optical
radiation (CIE 106/5, 1993).
The quantities can be converted backwards and
forwards; the conversion factor is strongly dependent
on the radiation spectrum of the light source. Table 3.2
gives the conversion factors for natural global radiation.
The conversion factors for different types of lights may
be considerably different.
PAR
Plants use a portion of the light for photosynthesis.
For this reason, this section – from 400 to 700 nm – is
Optical radiation is characterised by its wavelength,
which is expressed in nanometres (nm) or micrometres
(µm), with 1,000 nanometres equalling 1 micrometre.
known as photosynthetic active radiation (PAR). 201 Red
radiation (600 to 700 nm) is the most efficient for plant
photosynthesis;
Table 2.1: Breakdown of optical radiation.
Name Abbreviation Wavelength (nm) Comments
Table 2.2: Conversion factors of different quantities,
based on natural radiation.
Conversion into
Ultraviolet
radiation
UV
UV-C
UV-B
< 280
280-315
does not reach <300
nm Earth's surface
µmol m -2 s -1 W PAR m -2 W m -2 klux
Photosynthetic
active radiation
Near infrared
radiation
Far infrared
radiation
PAR
NIR
UV-A
B (blue)
G (green)
R (red)
FR (far-red)
NIR
315-400
400-500
500-600
600-700
700-800
800-3.000
FIR 3.000 – 100.000
Conversion from
µmol m -2 s -1 1 0,22 0,43 0,056
W PAR m -2 4,6 1 2 0,26
W m -2 2,3 0,5 1 0,13
klux 18 4 8 1
Source: Kasalsenergiebron.nl /Agrotechnology & Food Innovations B.V.
Member of Wageningen UR
Source: Kasalsenergiebron.nl /Agrotechnology & Food Innovations B.V.
Member of Wageningen UR
A portion of the global radiation is visible to the human
eye, namely that part in the wavelength range of 380 to
780 nm. This is called visible light, and corresponds with
the colours blue, green, yellow, orange and red.
it contributes to chlorophyll synthesis and plays a role
in photoperiodism and photomorphogenesis. Green
radiation (500 to 600 nm) provokes the smallest
physiological response from the plants. Blue radiation
(400 to 500 nm) also contributes to photosynthesis, i.e.
Global radiation can be expressed in different quantities.
to plant growth, as well as to photomorphogenesis. 202
Meteorological data often use the radiation's energy
content, expressed in W m -2 .
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UV
UV radiation is the portion of global radiation that has the
most energy. So-called UVB light (300 to 315 nm) and UVA
light (315 to 400 nm) are responsible for the breakdown of
substances such as plastics. It is therefore necessary to
protect window films and plastic sheets from UV degradation
(ageing) by adding UV stabilisers to the polymer. UV radiation
mainly affects plant photomorphogenesis and colour. A
small portion of the UV radiation is also used for plant growth
Solar radiation
For plants, the decisive factors are the radiation that
the sun emits and that reaches the earth, its quantity,
quality, and the changes due to astronomical and
meteorological effects.
and photosynthesis. 202
NIR
Near infrared (NIR), with a wavelength of 700-3,000 nm,
is the part of the solar spectrum that plants hardly use;
it is chiefly converted into heat (sensible and latent).
This can have a beneficial effect on the indoor climate
or, conversely, introduce the problem of overheating,
dependent on the season and location. The portion of
radiation from 700 to 800 nm is known as far red. It
plays a part in photomorphogenesis, in particular stem
elongation and photoperiodism in plants. 202
FIR
Far-infrared radiation (FIR), with wavelengths from
3,000 to 100,000 nm, does not result from direct solar
radiation. It is heat radiation, emitted from every warm
'body'. This radiation plays an important role in the
atmosphere, because it is partly responsible for the
greenhouse effect. The emission of far-infrared radiation
is isotropic and has the same spectral composition as a
black body. Planck's radiation law applies here. A black
body emits energy with a spectral distribution over the
wavelengths according to the body's temperature. The
maximum intensity is 10 µm at a temperature of 293 K.
Before solar radiation reaches the earth, various effects
in the Earth's atmosphere cause it to be reduced. 203
- Scattering by air molecules
(Rayleigh scattering).
- Scattering and absorption by dust particles
and water droplets (Mie scattering). Scattering
varies according to the season. Scattering is at
its highest on warm, cloudy summer days and
minimal on cold, clear winter days. The diffuse
portion of global radiation increases as Mie
scattering increases.
- Absorption by ozone, water vapour and other
atmospheric gases. The main UV absorbers are
ozone, SO2 and NO2. Radiation at wavelengths
below 300 nm is absorbed completely by the
ozone layer. Water vapour (723 nm) and oxygen
(688 nm and 762 nm) absorb significant portions
of the red (600 to 700 nm) and far-red radiation
(700 to 800 nm). Portions of the heat radiation (>
3,000 nm) are absorbed by CO2.
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Global radiation
Once the solar radiation has been filtered through the
Earth's atmosphere, the so-called ‘global’ radiation
remains. Global radiation consists of two types of
radiation: direct and diffuse. Figure 2.2 shows the typical
course of global radiation in the Netherlands (SEL year,
based on KNMI data). According to the KNMI, the annual
radiation sum of the global radiation in the Netherlands
averaged over the years 1971 to 2000 is 1,027,777 Wh m -2
a -1 . On average, the radiation sum is approximately 600
Wh m -2 d -1 (2770 µmol m -2 ) in winter, and around 4500 Wh
m -2 d -1 (20730 µmol m -2 ) in summer. The average radiation
over the summer is around 270 W/m2, and in winter around
70 W/m2. The average maximum radiation is around twice
as high as the average radiation during daylight hours;
in winter it is three times higher. The absolute maximum
is around 880 Wm -2 (4030 µmol m -2 s -1 ) in summer and
around 350 Wm -2 (1600 µmol m -2 s -1 ) in winter. Around 50%
of the global radiation is in the PAR region of the spectrum,
and the other 50% in the NIR region.
µmol m -2 s -1 ) and around 70 W m -2 (320 µmol m -2 s -1 )
in winter (Table 3). Radiation sums for period such as
days, months or years are expressed in Joules (J). The
average monthly radiation sums in the Netherlands are
displayed in the graph below. The Netherlands receives
an average of 3650 MJ/m² in global radiation annually.
However, it should be noted that radiation sums have
been considerably higher in recent years.
Figure 2.2: Global radiation sums
in the Netherlands on a monthly basis.
Global radiationsum [Mj/m2]
600
500
400
300
200
100
0
70
135
246
390
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Source: wiki.groenkennisnet.nl/KNMI
512
529 525
463
309
191
85
55
The global radiation changes due to a number of
parameters, namely: the position of the sun, the latitude,
the season, the time of day, and the degree of cloud
cover. CIE 85 (1989) gives an overview of the intensity
and composition of the global radiation, depending on
the various parameters.
Solar radiation that reaches the Earth is also known
as global radiation. Global radiation is often expressed
in watts per square metre (W/m2). On a clear day in
summer, global radiation can reach more than 900 W/
m2. The average radiation over the hours of daylight
over the light hours is around 270 Wm -2 in summer (1250
Figure 2.3: Annual average global radiation sum (in J cm -2 )
for the Netherlands, derived from pyranometer measurements:
climatology over the period 1970 through 2000.
380 000
370 000
375 000
360 000
375 000 365 000
370 000
365 000
360 000
345 000
350 000
355 000
355 000
350 000
345 000
joules per cm2
340 000 - 345 000
345 000 - 350 000
350 000 - 355 000
355 000 - 360 000
360 000 - 365 000
365 000 - 370 000
370 000 - 375 000
375 000 - 380 000
380 000 - 385 000
Source: Global radiation measurement from space with the current generation METEOSAT
Hartwig Deneke, Robert Roebeling, Erwin Wolters and Arnout Feijt (KNMI)
33

The spectral distribution of global radiation varies under
different conditions. Thanks to the ozone layer in the
atmosphere, radiation below 300 nm is completely
absorbed. The thickness of this ozone layer increases as
the geographical latitude increases, with UV radiation
decreasing accordingly. UV radiation intensity increases
in the course of the year. For example, the proportion
of UV radiation (300-400 nm) with the sun at a higher
position during the summer months is higher, both in
absolute and relative terms, than with the sun at a lower
position during the winter months.
and water vapour in the air. At the end of the day, at dusk
(sun position below 10º), Rayleigh scattering increases
and the proportion of blue radiation increases in relative
terms (Smith, 1982).
Day length
Day length is never constant, due to the tilt of the Earth's
axis in relation to the ecliptic plane (the path on which
the Earth revolves around the sun). At the solstice that
takes place between 20 and 22 June, the North Pole of
the Earth is at its closest to the sun. At this time the day
length varies from just over 12 hours to the south of the
Tropic of Cancer to 24 hours inside the Arctic Circle. At
this time of year the sun never sets on the Arctic Circle.
In contrast to UV radiation, the proportion of NIR
radiation (800 to 3,000 nm) is relatively larger at lower
sun positions and smaller when the sun is at higher
positions. The proportion of NIR radiation decreases as
cloud cover increases.
The Rayleigh scattering in the atmosphere causes the
proportion of blue radiation to increase. When the sun
is higher in the sky - i.e. during the summer months –
the radiation intensity of the blue radiation increases.
Increased cloud cover in turn increases diffuse radiation,
and thus the proportion of blue radiation as well.
Conversely, the share of blue radiation decreases thanks
to increasing Mie scattering caused by dust particles
In the southern hemisphere the sun is in the sky for a
little less than twelve hours a day in the area north of
the Tropic of Capricorn. Inside the Antarctic Circle, the
sun doesn't rise above the horizon at all at that time.
During the autumnal equinox, which takes place on 22 or
23 September, neither pole is closer to the sun than the
other. As a consequence, the sun is in – and out of – the
sky for almost the same amount of time, everywhere in
the world, in that one 24-hour period.
During the solstice that occurs between 20 and 22
December, the South Pole of the Earth is closest to the
sun. As a result, day length in the southern hemisphere
varies from just over twelve hours in the area north of the
Tropic of Capricorn to 24 hours inside the Antarctic Circle.
In the northern hemisphere, the sun is in the sky for a
little less than 12 hours a day in the area south of the
Tropic of Cancer, and inside the Arctic Circle it does not
rise above the horizon at all.
34

35

Figure 2.4:
Day length – daylight on Earth on 21 June.
Figure 2.5:
Length of day and night depending on latitude.
Tropic of Cancer 23.5º N
equator
Tropic of Capricorn
23.5º S
Arctic Circle 66.5º N
Ecliptic
E≈23,44º
N
6 months (polar day)
24 hours
13½ hours
(sun at the zenith)
Arctic
arctic circle
tropic
equator
21-3
day
-
night
days drawing out
21-6 21-9 21-12 21-3
24 hour polar day
day
max
day
-
night
dagen korten
24 hour polar night
day
min
days drawing out
day - night day - night day - night
day
-
night
Antarctic Circle 66.5º S
polar night (6 months)
S
0 hours
10½ hours
12 hours
Day length
tropic
arctic circle
south pole
day
-
night
days shorten
dag
min
24 hour polar night
day
-
night
days drawing out
dag
max
24 hour polar day
days shorten
day
-
night
Source: Wikipedia
Source: Wikipedia
In both hemispheres, the higher the latitude, the shorter
the day length in winter. Between the summer and winter
solstices the day length decreases, and from the winter
to the summer solstice it increases. The increase or
decrease is faster during the time near the equinox and
the higher the latitude. As a result, at 60 degrees latitude
in both the northern and southern hemispheres, the day
when measured by clock time rather than solar time, the
shifts in the time of sunrise are usually not the same as
those of sunset. The length of the day is not most closely
related to the sidereal day, the rotation of the Earth
around its axis in 23 hours, 56 minutes and 4 seconds,
but to the synodical day of 24 hours on average, in which
the rotation of the Earth around the sun also plays a role.
is only very brief during and just before and after the
winter solstice.
Sunrise and sunset times in the Netherlands each shift
by a maximum of about two minutes per 24-hour period
During the spring equinox, the day length is around
twelve hours everywhere except at the poles. At 20
degrees latitude, day length at the winter solstice is
significantly longer, and the increase or decrease in day
length just before or after the solstice is slower here. The
(aside from the one-hour jumps caused by the change
between summer and winter time), so that the time in
between changes by a maximum of about four minutes
per 24-hour period. In December and June the changes
are very small.
same applies, in reverse, to the 24-hour period during
which the sun doesn't rise above the horizon at the
different latitudes during and immediately before or after
the summer solstice and during the autumn equinox.
Sunrise (in the city of Utrecht, 2021) ranges from 5:18
am (summer time) to 8:48 am (winter time), while sunset
ranges from 4:27 pm (winter time) to 10:04 pm (summer
time). The difference in each case is about 4.5 hours,
As a result of the equation of time (the effect of the
change in the Earth's orbital velocity during the year),
always in small steps, minus one hour due to the change
between summer and winter time.
36

Figure2.6:
Day length as function of geographical latitude.
90
75
24 hour polar day
60
45
Geographic latitude (º)
30
15
0
-15
-30
-45
-60
-75
24 hour polar night
-90
30 60 90 120 150 180 210 240 270 300 330 360
Julian Day
Source: Wikipedia
The time at which the sun is at its peak on one day varies
from 12:23 to 12:54 pm (winter time) and from 1:36 to
1:46 pm (summer time).
The length of the day is important for plants; it signifies
the period for which radiation is available to the plant.
Day length varies depending on the season and the
latitude. Close to the equator (geographical latitude
0º) the day length, including dusk, remains almost
constant throughout the year at around 13 hours. In Oslo
(geographical latitude 60º) the day length is more than
22 hours in summer and less than eight in winter. The
difference in geographical latitude in the Netherlands is
small, with most of the horticultural regions located at
around 52º. The longest day is around 16.5 hours, and the
shortest less than eight. 204
Day length is not only important for the quantity of
radiation that plants are able to utilise for photosynthesis –
it is of particular importance to all the plant's photoperiodic
processes. Photoperiodism is plants' response to the
relative lengths of day and night phases in a 24-hour cycle.
A brief summary:
- Global radiation consists of direct radiation and
diffuse radiation.
- A number of parameters cause global radiation
to change in intensity and spectrum: the sun's
position, the latitude, the season, the time
of day, and the degree of cloud cover. This is
important because the results of the calculation
model described in this book are dependent on
the country for which the calculations are made.
The theory applies everywhere; the results of the
calculations according to the model vary.
- Daylight is the combination of all the light coming
from the sun during the day, whether directly or
indirectly. Forty percent of all solar energy that
reaches the Earth's surface is visible radiation.
The rest consists of ultraviolet (UV) or infrared
(IR) light. The amount of daylight is different in
different places and at different times, depending
on the position of the sun and the weather during
the day, the season, and the year.
37

38

39

Simply put: the amount of light on the ground depends
on the height of the sun (the higher the sun, the more
light on the ground).
Levels of daylight are markedly different on horizontal
vs vertical surfaces and at different seasons and times
of day. They are directly related to local sun paths and
weather conditions.
- Although electric light sources can be very close
to particular daylight spectrums, as of yet no light
sources have been developed that are able to
simulate the variations in the light spectrum that
occur at different times, in different seasons, and
in different weather conditions. (Source: Boyce
et al, 2003.)
- In the Netherlands, the intensity of global radiation
varies from an average of 70 W m -2 (320 μmo m -2
s -1 ) in winter to 270 W m -2 (1,250 µmol m -2 s -1 ) in
summer; the light sum is an average of 4,500 Wh/
m 2 (20,730 µmol m -2 ) in summer and 600 Wh/m 2
(2,770 µmol m -2 ) in winter.
- The radiation spectrum of the global radiation
consists of UV B (300 to 315 nm), UV A (315 to 400
nm), PAR (400 to 700 nm), NIR (700 to 3,000 nm);
radiation above 3,000 nm is heat radiation (FIR).
In the Netherlands, day length varies from around
eight hours in winter to 16.5 hours in summer.
Daylight systems
Daylight systems enable the use of natural light in
a targeted manner in and around buildings. This is
achieved by placing windows or other transparent
materials and reflective surfaces in such a way that the
natural light provides efficient internal lighting during
daytime. In order for a daylight system to work properly,
specific assessments must be made at all stages
of the building design process, from site planning to
architectural design to interior and lighting design.
Daylight in buildings comprises various factors: direct
sunlight, diffuse light from the sky, and light reflected
from the ground and surrounding objects. The design of
a daylight system must take the location and specific
characteristics of the building site into account, as
well as the characteristics of the façade and the roof,
the size and location of window openings, glazing and
solar shading, and also the geometry and reflection
coefficient of interior surfaces. A well-designed daylight
system ensures that there is sufficient daylight
throughout the day.
Some basic characteristics of daylight outdoors:
- Direct sunlight is extremely intense and
constantly changing. The amount of light that
it creates on the Earth's surface can exceed
100,000 lux. The brightness of direct sunlight
varies according to the season, the time of day,
the location, and the weather conditions. In sunny
climates there is a need for well-thought-out
architectural design, with careful management of
the amount of sunlight admitted along with how it
is dispersed, shaded, and reflected.
- Sky light is sunlight that is scattered by the
atmosphere and the clouds, creating soft, diffuse
light. The light intensity emitted by a dark sky can
be up to 10,000 lux in winter and up to 30,000 lux
on a sunny summer's day with plenty of cloud. In
cloudy climates, diffuse sky light is often the main
source of usable daylight.
40

- Reflected light is light – both sunlight and sky
light – that is reflected by its surroundings: from
the ground, trees, vegetation, nearby buildings,
and so forth. The reflection coefficient of the
surrounding surfaces has an impact on the total
amount of light that falls on a building's façade.
In some densely built-up environments, the light
reflected from the ground and the surroundings
can make a significant contribution to the daylight
that enters the building.
When creating a daylight system for a space, the
objectives are: good lighting for visual tasks, the creation
of a visually attractive environment, saving energy, and
providing light for the biological needs of the human body.
A well-lit environment is simultaneously comfortable,
pleasant, relevant, and appropriate, both for the intended
use and for the users of the space. 205
Daylight systems can be simple: from combining
window design with appropriate internal and external
solar shading, all the way through to complete systems
designed to direct sunlight or sky light to the places it
is needed. More advanced systems can be designed to
follow the sun or passively direct sunlight and sky light.
Daylight systems are inextricably linked to a building's
energy requirements and to the indoor climate. The
size and location of the glazing must be determined in
conjunction with a building's total energy consumption
and the specific requirements for a daylight system.
The availability of daylight
The primary purpose of daylight systems for buildings
is generally to provide sufficient light in the room and at
the workstation, in such a way that daylight is the main
(or only) source of light during the day. There are several
criteria for the availability of daylight for tasks and/or
rooms. An important aspect of daylight that must be
considered is that daylight is variable: it varies according
to the time of day, the season, and the weather
conditions. This means that the criteria for calculating
the availability of daylight are based on relative values
more often than on absolute values. They are usually
defined in terms of the relationship between the
available light at different locations inside the building,
and the available light outside (for example the daylight
factor, or DF).
The absolute illuminance that is required for a specific
visual task is dependent on the nature of the task and
the visual environment in which it will be carried out. For
example, the Chartered Institution of Building Services
Engineers (CIBSE) recommends the following luminous
intensities. 206
- 100 lux for interiors where movement is required
for the visual tasks, but where details do not need
to be clearly visible.
- 300 lux for interiors in which fairly simple visual
tasks are carried out .
- 500 lux for interiors in which fairly complex visual
tasks are carried out and it may be necessary to
make a clear distinction between colours (e.g. in
the average office or in kitchens).
- 1,000 lux for interiors in which highly complex
visual tasks are carried out, with a need for even
small details to be visible.
41

42

Views
Satisfying the need for contact with the outside world
is an important psychological aspect of daylight
systems. 207 Windows provide contact with the outside
world, assist with orientation, allow building occupants
to know when the weather changes, and enable them to
track the passage of time during the day.
Views of strips of sky, city or landscape help to relieve
monotony and lessen the feeling of being 'locked up'.
The eye level of a building's occupants is an important
consideration when making a well-thought-out choice of
window system formats and positions. 208
In the Netherlands, for a space in a house or an
office to be considered habitable according to the
building regulations, there must be sufficient natural
light available.
The standard for this is set down in the Building Code
(NEN 2057). The Building Code states that, as a rule of
thumb, the glass area must consist of a minimum of 10%
of the usable floor space.
Vondellaan nursing home, looking at how residents
respond to daylight simulation in the living areas of the
facility. The research was carried out in conjunction with
University College Roosevelt.
People with dementia exhibit behavioural problems
(anxiety, confusion, apathy) and sleep problems
(sundowning, sleeping during the day, night-time
restlessness). These problems impact the resident's
wellbeing and affect the work of the care staff.
Behavioural and sleep problems can (partly) be caused
by a disturbance in the resident's day and night rhythm.
The researchers looked at the effect that bringing
daylight into the building had on residents' behaviour,
sleep, and day and night rhythms.
The living areas of the Ter Reede Vondellaan nursing
home are therefore all equipped with so-called daylight
lamps. The light intensity prior to introducing daylight
varied from 50 to 200 lux. After daylight was introduced,
the light value in the living room rose to around 1,300 lux
– a considerable difference. Measurements were taken
both before and after the introduction of daylight.
When there is insufficient daylight, artificial light is
an alternative. Artificial light is created by converting
(electrical) energy into visible light (e.g. an incandescent
lamp, fluorescent lamp, LED lamp etc). The CIE standard
that simulates the complete daylight spectrum is called
light source D65.
Daylight simulation is used in various settings including
cattle breeding, horticulture, and care facilities. In mid-
2015, WVO Zorg commenced a study in the Ter Reede
The residents' activity patterns were measured using
Fitbit activity trackers. We then see a significant
difference in activity prior to and after the introduction
of daylight. In mornings and afternoyons we see that
the residents are significantly more active following the
introduction of daylight. In the evening and at night we
see a decrease in activity, more moments of rest. The
conclusion can be drawn that daylight has a positive
effect on residents' activity levels.
43

The residents' sleep efficiency was measured as well – again, both
before and after the introduction of daylight. We see that night-time
sleep efficiency during the night has increased significantly, from
86% before the introduction of daylight to 92% afterwards. The figures
represent an average for all residents, including those without problems;
both residents who already slept well and residents with disturbed day
and night-time rhythms. If we zoom in on residents with disturbed day
and night rhythms, we see a a very significant improvement in sleep
efficiency for them in particular. The conclusion is that light therapy
(daylight) has a positive effect on sleep efficiency.
Research was also conducted into the effect that daylight had on
the residents' behaviour. We then see that the scores for affect (the
measure of anxiety and mood) improved significantly once daylight
was introduced. We also see a trend towards improved cognition. In
other words, daylight has a positive effect on residents' behaviour.
These results are reflected in the daylight projects in the Willibrord and
Picassoplein nursing homes. One exceptionally good outcome is that
once daylight was introduced, the number of falls in the living areas was
reduced to virtually zero. 209
201. CIE 106/8, 1993.
202. CIE 106/5, 1993.
203. CIE 85, 1989.
204. Horn, 1996.
205. Lam, 1977.
206. CIBSE, 2006.
207. Robbins, 1986.
208. Boyce et al, 2003.
209. www.wvozorg.nl/over-wvo-zorg/
innovatieprojecten/daglichtsimulatie.
44

45

46

3DAYLIGHT IN BUILDINGS
47

THE BUILDING ENVELOPE
The concept of the building envelope, or 'shell' of the building, is related to the design and construction
of a building's exterior. The key elements for designing a good outer shell for a building are:
- The use of good materials for the façade and roof;
- Climate influences must be taken into account;
- Aesthetic elements (shape, colour, use of materials, and finish).
The building envelope consists of: the roof, the walls, any additional stories, and the doors and windows.
The building envelope allows light and air to enter and
leave the building (or prevents them doing so), which is
also linked to the desired indoor environment. The building
materials used are influenced by technological progress.
They increasingly allow building occupants to use the
surroundings to influence conditions within the building.
The walls of the building have a structural function in
addition to their role as partitions and boundaries. Along
with the upper stories of the building, they give strength
to the structure and support the roof. In order to ensure a
comfortable environment in the building, the design of the
building envelope should take a number of key aspects
into account, such as ventilation, humidity, the incidence
of light, and the temperature. These aspects are essential
to the welfare and wellbeing of building occupants.
In general it can be said that the building envelope is
dynamic, and is therefore able to respond to changing
environmental conditions. This means that not only
does the envelope make a significant contribution to
the health and wellbeing of those who use the building,
but the building envelope also offers opportunities to
increase the building's energy efficiency.
The façade
The façade of a building is the visible exterior, consisting
of a front and rear façade as well as the side walls.
Stone, wood, glass and metal are commonly used for the
façade. The lower part of the façade, sometimes called
the plinth, is in many cases different from the rest of
the façade. An important reason for this is that the lower
part of the façade has an additional function in many
cases: it houses the entrance to the building.
A façade's architecture is determined by the shape, the
materials used, the location, the size and shape of the
openings (doors and windows), and the presence of other
shape-defining elements. The façade has a number of
functions, regardless of the building's purpose:
- insulating temperature and sound;
- sealing out water and enabling moisture control;
- regulating levels of natural light or shutting it out
(solar shading);
- transferring the weight from outside, from inside
and its own weight;
- views and visual effects;
- allowing or closing off entry to the building;
- the appearance: image, culture and architecture.
Requirements regarding the forces on the façade vary
according to the building's purpose and immediate
surroundings. These requirements involve regulations,
costs, materials and the like, and may vary considerably
48

from country to country. The EPBD states that from 2020
onwards, all new buildings must be (nearly) energyneutral.
Scientists agree that this requirement can only
be met by optimising the building envelope.
Openings in the façade make parts of the building
envelope transparent. In general openings have two
functions: to allow daylight in (windows), and providing
access to the building (doors). Solar shading, along
with the glazing and related frames, forms part of the
transparent area of the building envelope.
It's not surprising that glass surfaces play an important
role in the building envelope, as these are the places in
which light and warmth transmission is highest. The level
of transmission varies throughout the year.
Efforts to achieve improved building energy performance
are therefore largely aimed at better insulation and
managing energy transmission through glass surfaces.
Solar shading is essential when considering this aspect
of building design and should be integrated in the design
at an early stage.
This also enables the building's heating and cooling
systems to be scaled accordingly, which has a positive
effect on construction and operating costs.
Daylight
Factors that influence building occupants' comfort and
wellbeing include:
- the thermal comfort;
- the natural light;
- the visual comfort, and the contact with the
outside world.
Thermal comfort
Thermal comfort includes 'feeling hot or cold', draughts,
and the discomfort of cold floors. It refers to the
perceived temperatures in a building. There are a
range of factors that determine thermal comfort, such
as the exterior climate (wind, sun and temperature),
the building's insulation, the glass surfaces, and the
capacity and quality of the building's heating, cooling
and ventilation systems.
Sustainable thermal comfort can generally best be
achieved in building envelope concepts featuring
variable thermal light transmission properties. Buildings
can thus best adapt to changing internal and external
conditions, according to the building's intended purpose.
In the building envelope, the intended improvement
of visual and thermal quality is ideally paired with a
substantial reduction in energy consumption for heating,
cooling, air recirculation, and lighting.
Research into thermal comfort has shown that, amongst
other things:
- people get used to the average thermal conditions
to which they are exposed;
- comfort temperatures are therefore variable;
- although there is no particular temperature at
which everybody feels comfortable, the ideal
temperature is between 17 and 30°C (depending
on social and cultural practices).
People are not simply the passive recipients of a thermal
environment; they interact with their surroundings
continuously. When they feel discomfort they take
corrective actions, such as turning the heating up or down.
49

There are various forms of adaptation to discomfort:
influencing the environment (opening windows, using
solar shading), adapting behaviour (adding/removing
items of clothing or changing the type of clothing) and
adapting psychologically. People's performance shows a
reduction of 10% or more as soon as the temperature in a
building rises above 30°C or falls below 15°C.
Thermal comfort is achieved by allowing the temperature
to vary along with the outdoor temperature (within
a certain bandwidth). The human body can function
perfectly in a naturally ventilated environment where
users have individual control. Occupants should
therefore have as many options as possible for finding
a balance between the comfort temperature and the
temperature of their surroundings, such as windows that
can be opened, dynamic solar shading and ventilation.
- maximum use of natural light with minimal
reflection gives an average of 4% improvement in
productivity;
- direct exposure to (excessive) sunlight in
classrooms, particularly through unprotected
east- and south-facing façades, reduces student
performance by 20 to 25%;
- thanks to access to daylight, students achieve an
improvement of 5 to 14% in exam results and learn
20 to 26% faster.
Visual comfort and contact with the outside world
Visual comfort is determined by the absolute quantity
of light and the luminance ratios within the field of view.
Luminance is the physical variable which is commonly
referred to as 'brightness'. Reflection or glare is an
important aspect.
Natural light
The human body uses natural light in the same way
as water and food: as a raw material for metabolic
processes.
Research shows a direct correlation between wellbeing
and the presence of natural light in areas of buildings
where people spend time.
A few facts taken from various scientific studies:
- daylight in areas where people work reduces
absenteeism (an improvement of up to 6.5
percentage points) and promotes a good night's
sleep (more than 45 minutes more sleep);
- when daylight is present, people are
approximately 18% more productive in their work
and retail sales are 15 to 40% higher;
Sunlight reflects when it falls on surfaces. Inside buildings
it is particularly annoying on, for example, monitors.
Windows in a building fulfil an important human need:
visual contact with the outside world. A very brief
summary of conclusions from the many scientific
studies in this area:
- The health problems of people who are close to a
window while at work are reduced by 20 to 25%.
Absenteeism decreases by 15%.
- Having a view of the outside world improves
mental functioning, including memory, by 10 to
25% and discussions are finalised 6 to 12% faster.
- A view of the outside world greatly accelerates
healing processes; research shows that this
reduces hospital stays by 8.5% on average.
50

51

52

4
DYNAMIC SOLAR SHADING IN BUILDINGS
53

THE IMPACT OF DAYLIGHT ON ENERGY CONSUMPTION
Effect Difference Source
1 Use of (adequate) daylight
reduces energy consumption
2 Optimisation of daylight
reduces energy consumption
in buildings
(See: www.wbdg.org and www.archlighting.com)
20% International Journal of
Smart Grid and Clean Energy
2012
15 to 20% National Technical University
of Athens (Doulos & Topalis)
2014
An interesting study from 2012 provides insight into
the energy consumption of all existing office buildings in
New York City:
When enough daylight is available the dimmable lighting
controls can turn out all the lights or reduce the wattage
used per square metre. Along with adjusting electric
lighting to the amount of daylight available, dimmable
lighting presents the user with another major benefit:
matching the electric lighting to the activities carried out
in the space. Generally, the light intensity in offices is set
at a high level for all spaces, regardless of their use.
This implies that an intrinsic and significant amount of
wasted energy could be saved.
Energy consumption
Indoor lighting 26%
Outdoor lighting 6%
Cooling 17%
Ventilation 15%
Heating 3%
Equipment and other 33%
100%
Equipping New York’s 35 million m2 office building stock
with dynamic solar shading would result in a staggering
70 million dollars in annual energy savings.
Compared to conventional systems that merely comply
with the regulations, the latest dynamic solar shading
systems have the advantage of generating more savings
due to their ability to adapt the intensity of light to the
occupants’ needs and to daylight saving.
This can also provide benefits in the areas of health and
productivity. Sensors observe daylight in a space and
will automatically adjust the electric lighting in order to
maintain the required overall light intensity while saving a
significant amount of power.
It is easy enough to measure the lighting levels of
artificial lighting, but the quality of daylight in a space is
much more difficult to quantify.
To maximise the effect of advanced daylight systems,
the integration of dynamic solar shading is nearly
always necessary. Optimal lighting design should also
complement the interior design and finishes.
The colour of floor coverings, walls and furniture, the
height and level of transparency of partition walls - as
well as their properties - can all have a huge impact on
the resulting light levels and the opportunity to make the
best possible use of daylight in the space.
What is also essential is the correct operation of
advanced daylight systems, as well as ongoing
maintenance and training for users. Operators and users
of a building will need to understand how the system
is designed to function and technical managers need
to know how they can keep the systems in perfect
working order. 401
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55

The value of dynamic solar shading
in energy management
Dynamic solar shading prevents overheating. Even in
the colder seasons NZEBs (nearly zero-energy buildings)
have increased demand for cooling in order to prevent
overheating due to thick insulation layers and airtightness.
Reports on climate change and the EPBD
(Energy Performance of Building Directive) recommend
solar shading as one of the most energy efficient
solutions available.
are the most effective, as they keep 90% of the incoming
solar heat out. Dynamic solar shading is not only valuable
in summer, but also during winter.
In summer:
- Solar shading helps keep the heat out of the
building as much as possible (reflection!) and
in doing so the building uses less energy, with a
decreased need for air-conditioning.
- In the evening the shading device and windows
can be opened to let fresh air flow into the
building. That inflowing air will then obviously
decrease the indoor temperature.
In winter:
- If the solar shading device stays open, sunlight
can freely enter the building, allowing the building
to maintain its temperature or reduce the need
for heating.
- After sundown windows and doors should
preferably be kept closed to prevent unwanted
heat loss.
Dynamic solar shading can be applied both inside
and outside the window and there is a whole range
of different devices to choose from. The option of
being able to move the light blocking elements of the
shading device, increases the benefits of using such
a system. For optimal effects, this movement should
be automated, depending on the conditions or any
(pre-set) parameters.
There are many different types of solar shading, both
for indoor and outdoor use, each with their own specific
properties and options. Outdoor solar shading and blinds
Optimum technical and visual comfort calls for
automated dynamic solar shading. When choosing the
type of sunlight or daylight shading system the following
factors are decisive:
- The local climate.
- The solar orientation of façades.
- The use of the building.
- The surroundings: obstacles and the effects
of shadows.
- The users of the building (privacy, contact with
the outside world).
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The full colour gamut of daylight is crucial to the general
well-being of people. Shading combined with clear
glazing guarantees a quality of daylight that exclusively
produces scattered light. The CRI scale measures how
accurately visual colours are displayed compared to ideal
or natural light.
The possibility of alternating solar gain with thermal
loss as a result of the positioning of the shading device
clearly shows to what extent dynamic shading systems
can outperform static glazing systems, as the optic
properties of the latter cannot be configured.
The full dynamic range of solar radiation admitted
into the building is very high for solar shading (CRI97
compared to CRI86 for reflective glass).
Important aspects of controlling sunlight and daylight for
improved comfort, health, productivity and well-being:
- Taking full advantage of natural light.
- Maintaining the complete gamut of external light.
- Prevention of glare and filtering of daylight.
- Minimisation of excessive heating.
Important aspects of controlling sunlight and daylight to
save on energy and costs related to cooling:
- Keeping heat outside in hot weather.
- The risk of buildings becoming overheated by the
high yields of insulation and airtight construction.
- The costs for heating will ultimately transfer to
costs for cooling, even in colder climates.
Important aspects of controlling sunlight and daylight to
save on energy and costs related to heating:
- Preserve solar energy during winter conditions.
- Improve insulation at night during winter
conditions.
When controlling solar light and daylight to save energy
and costs for heating, a lot of glazing is required in order
to capture enough daylight before the costs of lighting
will markedly decrease.
Capturing natural light saves energy
In a typical office building, between 25 and 35% of the
electricity costs are spent on lighting. Dynamic solar
shading uses natural light to reduce the need for artificial
lighting by 80% and guarantees solar gain for passive
heating. In the energy performance of buildings, as an
integral part of the building shell, dynamic solar shading
has upgraded itself from being a mere component to a
complete concept of sunlight and daylight control.
CO₂ footprint of solar shading systems
Solar shading is cost-effective with energy savings of up
to 60 times the related CO₂ footprint during its lifecycle
of 20 years. The Würzburg-Schweinfurt Institute in
Germany calculated the CO₂ footprint at the request of
the Greenhouse Gas Protocol of the World Resources
Institute (WRI) and the World Business Council for
Sustainable Development (WBCSD). Calculations were
based on motorised, typical exterior blinds with 80 slats,
measuring 1.2 x 2.0 m. Results show that 86% of CO₂
emissions are created during extraction of raw materials
and production of primary products, whereas only 0.5% is
created during the production process itself.
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58

Given a lifecycle of 20 years, 11% of emissions are produced during the
operational phase, while transport and waste account for 2,4%.
So, during its life a blind will produce the equivalent of approximately 150 kg
of CO₂ emissions. However, the blind’s protection against sunlight saves over
8,500 kg of CO2, which is a 57-fold improvement. Other types of exterior solar
shading, particularly exterior roller blinds and screens with various types of
reflective materials offer better energy savings and CO₂ footprint, because they
usually generate less CO₂ during the production process.
Energy savings related to cooling
Dynamic solar shading results in average energy savings for cooling of over
36% based on the mean of all glazing types and climatic conditions in Europe.
Energy savings for cooling are greater in façades facing the south-east and
west. Mean energy savings can amount to approximately 60%.
The highest energy savings for cooling can be achieved in south-west facing
façades. Exterior shading systems with the highest efficiency may reduce
solar energy or g-values to values of only 0.02 for all types of glazing.
Energy savings related to heating
Decreasing the u-values during the night by shutting solar shading devices has
a positive effect on the need for heating spaces in all European climate types.
Glazing ID Glazing Rome Brussels Stockholm Budapest
Int. Ext. Int. Ext. Int. Ext. Int. Ext.
A Single Clear 36% 71% 31% 64% 33% 66% 32% 65%
B Double Clear 33% 70% 25% 59% 29% 65% 27% 62%
C Heat Control 35% 67% 24% 53% 29% 61% 27% 57%
D Solar Control 31% 63% 24% 51% 25% 58% 26% 54%
E Triple Clear 32% 68% 24% 56% 28% 63% 26% 59%
F Double Clear Low-E 33% 69% 25% 55% 29% 63% 27% 59%
401. ‘’Let There Be Daylight: Retrofitting daylight controls in NYC office buildings’’ Green Light New York, 2012.
59

60

OFFICES
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62

5
PEOPLE IN OFFICE BUILDINGS
63

INTERACTION BETWEEN BUILDINGS, OCCUPANTS
AND SURROUNDINGS
What might at first seem like a simple improvement in staff health and productivity can have
a big financial impact on organisations that employ, train or provide staff. After all, staffing
costs – including salary and social benefits – usually account for more than 50% of the running
costs of offices, schools and hospitals. This is far more than any other financial saving associated
with a building that is efficiently designed and run.
All over the world, scientists and experts study factors
that can influence elements of building design: air
quality, thermal comfort, the use of daylight, acoustics,
interior design, and views to outside. The effects of
location and facilities are considered too.
When we consider the available evidence, research
makes it clear that office design has a material effect
on the health, wellbeing and productivity of office
occupants. This may seem obvious, but it could be
argued that the evidence has not yet been widely
translated into design and financial policy everywhere in
the world. When gathering this evidence, it is important
to create momentum and, for example, to also give real
estate professionals the communication tools they need
in order to bring change.
Strategies can be implemented that combine maximum
health with productivity, while at the same time developing
methods that limit the use of energy and raw materials.
Clearly there is often a 'virtuous cycle' of smart design that
is good for people and the planet, for example maximising
daylight while also allowing users to have control.
But alongside the win-win situations there are
contradictions and challenges too, especially in hot and
humid regions. This demonstrates the importance of
continuous product and system innovation.
In any case, the findings confirm beyond doubt that
buildings can provide maximum benefit to people while
at the same time being sustainable and using resources
responsibly. Low carbon emissions, resource efficiency,
health and productivity are undeniably linked to better
building quality.
Terminology
The terms ‘health’, ‘wellbeing’ and ‘productivity’ are
used in an attempt to describe a whole range of
related and complex issues. Health encompasses both
physical and mental health, while wellbeing refers to
broader feelings and perceptions of satisfaction and
happiness. Productivity is often used with a focus
on business-oriented results. It covers a number of
different standards related to performance. However, it
is directly influenced by health and wellbeing, so making
distinctions between the three is not always easy, nor
meaningful.
Use of daylight and lighting
Good lighting is essential to employee satisfaction, and
our understanding of light's contribution to health and
wellbeing is still growing. It is not easy to separate the
advantages of daylight, which are obviously greater
near a window, from the advantages of the view from
the window. Various studies over the past decade have
shown that productivity increases when near windows.
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"We shape our buildings;
thereafter they shape us."
Winston Churchill
65

Experts now believe that the view is a major factor in
this, especially when the window looks out on natural
surroundings.
Indoor air quality
The health and productivity benefits of good indoor
air quality have been clearly specified. The quality is
defined in terms of (low) concentrations of CO₂ and
pollutants, and by air velocity. It would be unwise
to suggest that the results of individual studies, or
even meta-analyses, can easily be replicated for all
organisations. However, with this important caveat,
we can state that extensive research indicates that
an 8 to 11% improvement in productivity resulting from
increased air quality is not unusual.
Thermal comfort
This is closely related to indoor air quality and here, too,
it is difficult to see the benefits in isolation. Research
shows that thermal comfort has a major influence on
workplace satisfaction. The specific circumstances are
very important, making it unfeasible to suggest a general
rule regarding the level of productivity improvement.
Nonetheless, the studies consistently show that giving
building occupants even minimal control over thermal
comfort means an increase in productivity levels. The
importance of personal control is also relevant to other
factors, such as lighting.
Noise
In today's knowledge-based office, it is almost
impossible to be productive when noise causes a
distraction. This can be the biggest cause of staff
dissatisfaction.
Biophilic design
The rise of biophilic design, the idea that we have
an instinctive connection with nature, is a growing
research theme. An increasing scientific understanding
of biophilic design – along with the positive effect
that green space and nature have on mental health
in particular – has implications for those involved
in designing and fitting out offices, as well as for
developers and urban planners.
Interior layout
Being distracted by noise is an issue that is closely (but
certainly not exclusively) related to interior layout. There
are a large number of layout issues that can impact
on wellbeing and productivity, including workstation
density and the configuration of work areas and social
space. These factors impact not only on noise, but on
concentration, collaboration, privacy and creativity
as well. Many companies are instinctively aware of
this, and work together to try to find the best possible
configuration.
Look and feel
The same can be said of research on the 'look and
feel' of the office. Some consider it superficial, but it is
nonetheless taken seriously due to its potential impact
on the wellbeing and mindset of both employees and
visitors. The subjective way that people experience look
and feel (and interior layout) is probably different for
people of different ages, sexes and cultures.
Active design & movement
Movement is a proven method for improving health.
Movement can be stimulated through active design
66

inside the building and access to services and facilities
such as gyms, bike racks and green spaces, some of
which may be located inside the building, on the grounds,
or close by. Not much research has been conducted
on the link between exercise and productivity in the
office, although the studies that do exist point to lower
absenteeism amongst employees who cycle to work.
Facilities & location
Studies are increasingly recognising that it is important
to staff that facilities and services are available locally.
Childcare in particular can mean the difference between
working or not on any given day, and the few studies
that have attempted to calculate this demonstrate a
significant financial impact for employers.
Only the first three of the above design factors are
directly related to the building envelope, and two of them
are related to managing natural light. We will focus on
thermal comfort and the use of daylight, as this is our
area of expertise.
Windows are the main interface between staff at work
in buildings and the external environment. They are not
only a potential source of daylight and views, but also
of sunlight, glare, and potential overheating. Windows
that can be opened can allow noise and pollution to
penetrate, but when combined with a natural ventilation
system, they can reduce the need for mechanical
ventilation and cooling. Achieving the right balance
between all these factors can be challenging – and
costly. The façade represents a large part of the
overall cost of a new building; up to one-third of the
construction budget.
Thermal comfort
Whether thermal comfort is perceived as too low or too
high, the temperature is a hot topic in the workplace.
The thermal environment includes the air temperature,
the temperature of surrounding surfaces, the speed of
air flow, and the humidity level. The way that someone
perceives thermal comfort depends on their metabolic
rate, clothing and personal preference.
Within a certain temperature range – for example
between 16 and 24 degrees Celsius – there are not the
same immediate health risks as those posed by poor air
quality. 501
Studies have even shown that people can adapt
amazingly well to temperature, but not to, for example,
air quality. 502
However, this doesn't mean that thermal comfort is not
important to staff – far from it. Despite the fact that it is
difficult to measure the effect that thermal parameters
have on productivity, most research suggests that
moderately high temperatures are less well tolerated
than low temperatures, and there are many publications
that show that the perception of thermal comfort has a
203, 204
big impact on satisfaction in the workplace.
When it comes to thermal comfort, user control is an
important factor. When staff are able to adapt to their
environment by wearing the right clothing, varying the
air velocity over their bodies or making adjustments
to the solar shading, they are able to tolerate greater
temperature variations. A 2006 analysis of 24 studies of
the relationship between temperature and performance
67

showed a 10% reduction in performance at 30 degrees
and at 15 degrees, compared to a baseline of 21 to 23
degrees. This left little doubt as to thermal comfort's
effect on office workers. 505 A more recent study
under controlled conditions showed a 4% reduction in
performance at lower temperatures and a 6% reduction
at higher temperatures. 506
Thermal comfort is essential for a satisfied and
productive office workforce. It can be improved by
allowing building occupants to control and adjust it, as
well as by setting the ambient temperature just above
the air temperature. Of course, heating and cooling
strategies have a major impact on energy consumption.
Most offices only have requirements for regulating the air
temperature. Thermal comfort can be improved (which
in turn limits energy consumption) by focusing on how
the ambient temperature can actively be regulated even
during the building's design phase.
Like traditional radiators, cooled ceilings are a solution
in which heat exchange takes place via radiation and
convection processes. This has the advantage of
providing better thermal comfort, and is a more effective
way of generating and transporting cooling.
This implies that higher air temperatures can be
tolerated in summer, when the ambient temperature is
lower. In winter, the reverse is true. In naturally ventilated
buildings, night ventilation can pre-cool the open
thermal mass. This gives the workforce the benefit of
radiant cooling the following day, increasing the feeling
of comfort when there are higher air temperatures.
To put it more simply: when office workers have more
control over their environment, they are generally more
satisfied. 507 One study found that individual control of
temperature (within a 4°C range) led to a 3% increase
in logical thinking and a 7% increase in typing speed. 208
Another study suggests that a 3% gain in overall
68

productivity can be achieved by giving staff control of
the workplace temperature. 509
Likewise, allowing staff to have individual control of
light levels by installing dimmers in the office can
lead to increased satisfaction and improved mood. 510
Subsequent research added comfort, improved
motivation and increased ease in completing tasks to
the list of benefits. 511
Use of daylight and lighting
Lighting in a building is obviously important. Lighting in
offices must meet a number of needs. Naturally we need
to be able to see what we're doing, but lighting also affects
a number of other aspects of wellbeing, including comfort,
communication, mood, health, safety and aesthetics.
The lighting quality consists of a complex mix of light
intensity and spectrum, while the interplay of light and
shadow gives a room character and helps building
occupants to relax their eyes and to concentrate. Poor
visibility, glare, flicker and lack of ability to control the
visual environment can all affect performance, with
visual discomfort often resulting in headaches and
eye strain. Light is also essential for maintaining our
circadian rhythms.
In general the evidence is unequivocal: office workers prefer
to have access to windows and daylight, which consistently
provide benefits in terms of happiness and health. However,
it is difficult to differentiate between the effects of daylight
and those of views through windows. An extensive study
conducted in 2008 carried out measurements of the
physical environment and staff satisfaction across 779
workstations in nine different buildings. It found that lack
of access to windows was the biggest risk factor when it
came to unhappiness about light. 512
A recent study by neuroscientists found that office
workers who had access to windows were exposed to
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70

173% more white light during working hours, and slept
for an average of 46 minutes longer each night. Workers
without access to windows scored worse than their
counterparts on the level of quality of life related to
physical problems and vitality. They also showed poorer
results in terms of overall sleep quality, sleep efficiency,
disturbed sleep, and dysfunction during the day. 513
A 2011 study examined the relationship between
quality of vision, regulation of daylight and sick leave
for administrative staff on the Northwestern University
campus. Together the two variables accounted for 6.5%
of the variation in sick leave, a statistically significant
difference. 514 Office workers prefer access to windows
and daylight, which provide consistent benefits in terms
of satisfaction and health.
Strategies for maximising daylight and creating optimum
lighting conditions, while keeping energy consumption
to a minimum, are important yet complex elements of
sustainable design.
A task lighting level of 300 to 500 lux is usually
recommended for offices; this is different to general office
lighting. It has been suggested that increased light intensity
might stimulate increased productivity but we should be
cautious about this. 515 Using artificial light to increase
light intensity involves an enormous amount of additional
energy consumption, and skilled lighting designers state
that office lighting of 300 lux is perfectly acceptable.
A common approach is to handle the task, the
surroundings and the background separately, with
more light on the task but less light in the surroundings
and background. The overall energy effect is a space
in which, as a rule, 50% of a softly-lit floor is used. The
space becomes more visually appealing too, although
the contrast should not be so great that it creates a
cavelike impression.
Regardless of the specific light intensities desired, it is
abundantly clear that the regulation of daylight needs to
be optimised; this is a win-win situation both for staff and
for energy consumption. Another advantage of daylight
is that it gives the highest levels of colour rendering, i.e. it
enables the true colour of an item to be better seen.
When designing for maximum daylight (and views),
designers should evaluate and consider a number of
environmental factors, including heat generation and
loss, glare control, visual quality, and variations in
available daylight across different seasons and weather
conditions. Appropriate solar shading inside and outside,
to control glare and reduce thermal radiation, helps to
achieve increased visual comfort and reduce the need
for additional cooling. Obviously this is much simpler for
new construction than in renovated buildings.
However, even when daylight is maximised, electric
lighting is evidently still required in some areas and at
some times of day. Lighting usually accounts for a quarter
of office energy consumption, which is why continuous
innovation in lighting design is vitally important.
LEDs are now a real alternative to conventional lighting, with
a level of efficiency exceeding that of traditional technology.
Innovation in lighting control is also very important,
particularly when individual control is encouraged.
71

501. Clements-Croome DJ. (2014) Duurzame Intelligente Gebouwen voor
betere gezondheid, comfort en welzijn, Rapport Denzero Project
ondersteund door de TÁMOP4.2.2.A-11/1/KONV-2012-0041 mede
gefinancierd door de Europese Unie en het Europees Sociaal Fonds.
502. Oh SYJ. (2005) Binnenluchtkwaliteit en productiviteit in kantoren in
Maleisië. BSc proefschrift, School of Construction Management and
Engineering, University of Reading, geciteerd in Clements-Croome D.
(2014) Intelligent Buildings, ICE.
503. Frontczak M. Schiavon S. Goins J. Arens E. Zhang H. Pawel Wargocki
P. (2012) Quantitative relationships between occupant satisfaction
and satisfaction aspects of indoor environmental quality and
building design. Indoor Air 22, pp 119–13.
504. Bijv. Leaman A. and Bordass B. (2007) Are users more tolerant
of ‘green’ buildings? Building Research and Information 35:6, pp
662 –673. Beschikbaar: http://www.usablebuildings.co.uk/Pages/
Unprotected/AreUsersTolerant. pdf Geraadpleegd op 13 augustus 2014.
505. Wargorcki P. (ed.) Seppänen O. (ed.) Andersson J. Boerstra
A. ClementsCroome D. Fitzner K. Hanssen SO. (2006) REHVA
Guidebook: Indoor Climate and Productivity In Offices.
506. Lan L. Wargocki P. Wyon DP. Lian Z. (2011) Effects of thermal
discomfort in an office on perceived air quality, SBS symptoms,
physiological responses, and human performance. Indoor Air 21:5,
pp 376-90.
507. Carnegie Mellon (2004) Guidelines for High Performance
Buildings - Ventilation and Productivity. Beschikbaar: http://
cbpd.arc.cmu.edu/ebids/images/group/ cases/mixed.pdf Laatst
benaderd op 5 augustus 2014 Development Securities (2010) A
report on the property industry’s key role in delivering a better
life in Britain: Building Quality of Life. Beschikbaar: http:// www.
developmentsecurities.com/devsecplc/dlibrary/documents/
QualityofLife_March2010.pdf Geraadpleegd op 13 augustus 2014.
508. Wyon DP. (1996) Indoor environmental effects on productivity.
Proceedings of IAQ’96 “Paths to Better Building Environments”,
pp 5-15, ASHRAE, Atlanta Wyon DP. Tham KW. Croxford B. Young
A. Oreszczyn T. (2000) The effects on health and self-estimated
productivity of two experimental interventions which reduced
airborne dust levels in office premises. Proceedings of Healthy
Buildings 2000, Helsinki, Finland, 1, pp 641-646.
509. Loftness V. Hartkopf V. en Gurtekin B. (2003) “Linking Energy to
Health and Productivity in the Built Environment: Evaluating the
Cost-Benefits of High Performance Building and Community Design
for Sustainability, Health and Productivity,” USGBC Green Build
Conference, 2003. Beschikbaar: http:cbpd. arc.cmu.edu/ebids
Geraadpleegd op 5 augustus 2014.
510. Newsham GR. en Veitch JA. (2001) Personal control firmly on the
switch. Canadian Property Management 16:4, pp 16.
511. Clements-Croome DJ. (2006) Creating the Productive Workplace,
Taylor and Francis, Abingdon.
512. Newsham GR. Aries M. Mancini S. and Faye G. (2008) Individual
Control of Electric Lighting in a Daylit Space. Lighting Research and
Technology 40, pp 25-41.
513. Chueng I. (2013) Impact of workplace daylight exposure on sleep,
physical activity, and quality of life. American Academy of Sleep
Medicine 36.
514. Elzeyadi I. (2011) Daylighting-Bias and Biophilia: Quantifying the
Impact of Daylighting on Occupant Health.
http://www. usgbc.org/sites/default/files/OR10_ Daylighting%20
Bias%20and%20 Biophilia.pdf Retrieved on 5 August 2014
515. Gou et al (2014) Building and Environment Journal [in press].
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6
OPTIMISING PRODUCTIVITY IN AN OFFICE ENVIRONMENT
BY CONTROLLING THE ADMISSION OF DAYLIGHT
75

BACKGROUND
Solar shading and daylight shading decrease the amount of heat that enters a building, and offer
dynamic possibilities for managing daylight. This helps lower the energy consumption used for cooling
and lighting in a building. 601, 602 Solar shading and daylight shading also affect comfort, wellness and
wellbeing and consequently impact the productivity of the building occupants. 603
This impact on building occupants is related to the influence of solar shading and daylight shading on
temperatures, the amount of daylight, the view from the window and the control over these aspects that
people feel they have. These factors greatly determine the level of satisfaction of building occupants and
may contribute to their productivity. This chapter summarises the results of a literature review and offers
insights into the degree to which these parameters of the indoor environment may influence productivity.
Based on the experience of experts and on the literature, a
number of factors have been determined that are affected
by solar shading and daylight shading, as shown in figure
6.1. 604, 605, 606 The relevant aspects are discussed and the
relevant parameters determined for assessment of the
productivity effects. The degree to which a specific solar
shading system or daylight shading system influences
these factors is dealt with elsewhere in this book.
Features of solar shading/daylight
shading system (Somfy)
Solar shading
Daylight shading
Environmental factors
Overheating
Heat radiation &
radiation asymmetry
Daylight
Figure 6.1:
Model summarising parameters
of the office environment
which may be influenced by the
solar shading and/or daylight
shading systems.
View
Control system
- Interface
- IT
- Hardware
Glare from daylight
and direct sunlight
Options for control
Noise
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Overheating
On a sunny day, the radiation from the sun contributes
significantly to the increase in temperature of a room.
In winter, this benefits energy conservation as less
heating is required from the heating systems.
In spring, autumn and summer, however, sunshine
can create an undesirable heat load which greatly
increases the temperature and requires energy
consumption for cooling.
It is especially large open spaces that experience poor
temperature distribution due to solar radiation on the
façade. If there are no separate heating control systems
for two opposite façades that include significant glazing
areas, the temperature in that part of the room closer to
solar radiation will be higher than in the part of the room
that is not in the sun.
If there is no cooling available, exterior blinds play an
important part in avoiding a temperature increase in
the room. If there is cooling available, exterior blinds
contribute to decreasing the cooling capacity required.
As a matter of fact, even on extremely hot days with
temperatures > 30°C, when cooling capacity may not
suffice in keeping the room at a reasonable temperature,
blinds will still limit the temperature increase in the room.
Heat radiation and radiation asymmetry
Solar radiation through a window creates a warm window
surface in the room. When window surfaces become hot,
the temperature in the room may be perceived to rise
because this large area radiates heat. Several models exist
that can predict thermal discomfort. They are based on
Based on four environment conditions (air temperature,
radiant temperature, atmospheric humidity and air
velocity) and two personal factors (clothing and activity),
the model predicts the average thermal sensations that
a group of people will experience. The result is the PMV
on a 7-point scale, ranging from cold (-3) to hot (+3). The
predicted value on the PMV scale represents an expected
percentage of people who are dissatisfied with the
temperature (PPD: Percentage of People Dissatisfied).
See table 6.1.
PMV
PPD
Table 6.1:
-3 Cold >90%
Scale of thermal
-2 Cool 75%
sensation and
-1 Slightly cool 25%
matching PPD value. 608
0 Neutral 5%
+1 Slightly warm 25%
+2 Warm 75%
+3 Hot >90%
This model facilitates calculations of the relative impact
of heat radiation on average thermal sensation. 609
An operative room temperature (air temperature and
radiation temperature combined) of 22°C in colder
seasons is generally considered neutral by people
working in an office and wearing winter clothing,
according to the model. When wearing summer clothes
this neutral temperature amounts to around 24 or 25°C.
This is based on an evenly distributed temperature,
without strongly divergent cold or heat radiation.
When solar rays hit a human body, the operative
temperature (air temperature and radiant temperature)
increases significantly.
Fanger's Predicted Mean Vote model (PMV model) (1970). 607
77

If we assume solar radiation of 700 W per m2 window
area and a room temperature of 22°C, the operative
temperature reaches about 30°C. This causes the PMV to
rise from 0 / neutral to 1.9 / warm. Thus, solar radiation
may be responsible for significant variations within
the indoor thermal climate and the predicted thermal
sensation (PMV value) in a room.
These variations in heat radiation on the human body
may cause local discomfort, for instance when an
individual is positioned perpendicularly to the façade and
in close proximity to the window, causing him/her to be
exposed to solar radiation on one side of the body only.
These variations in radiant heat (or radiant cold) between
two sides of the body is called radiation asymmetry. 610
It creates local thermal discomfort through uneven
distribution of the heat load on the body. 611
The case study of Marino et al. (2017) shows that solar
radiation is the main cause of discomfort caused
by radiation asymmetry. 612 The degree to which the
asymmetry contributes to dissatisfaction with the
temperature depends on the location of the surface
(ceiling or wall) and on whether it relates to cold or heat
radiation. 613 A warm window surface generally does
not lead to feelings of local discomfort due to radiation
asymmetry until the temperature reaches 23°C.
The impact of solar radiation on an individual will thus
mainly lead to thermal discomfort because of an overall
feeling of heat.
When solar shading is not present, the risk of thermal
discomfort on a sunny day is therefore high, even if the
building includes cooling systems.
Daylight
Daylight contributes to a decrease in energy
consumption used for artificial light and benefits
people's wellbeing. The amount of exposure to daylight
that building occupants enjoy depends on the design of
the building (e.g. surface area of windows in the façade
and façade orientation) and the location of the
workstation in the building (e.g. distance from the window
and orientation with respect to the window).
The daylight factor may be used to express the amount
of daylight in a workplace; this factor represents the
relation between the luminance in a spot in the room
and the simultaneous luminance outdoors. In offices
in the Netherlands, all workplaces generally have access
to daylight and the average daylight factor is at least
2 to 3%. 609
78

79

80

daylight and sunlight and, consequently, the influence on
the indoor thermal climate and the visual environment.
View
A pleasant view from the window is considered important
by many people. An unpleasant view contributes to
dissatisfaction about the workplace. The quality of the
view matters: views of green spaces/nature, visibility
of the weather and a horizon/objects in the distance
play a large part. A view of an atrium is therefore often
considered dissatisfactory.
The fact that allowing control of the indoor environment
increases users’ satisfaction may partly be explained
by the large individual variations in preference that
exist regarding temperature and lighting conditions.
The degree of an individual's control over the indoor
environment can be expressed by several parameters:
- Availability of control: is there an option to adjust
the indoor environment?
- Perception of control: does an individual feel they
have an option to adjust the indoor environment?
- Exercising control: actual actions that lead to an
adjustment of the indoor environment.
Glare from daylight and direct sunlight
The level of brightness of daylight and the direction of
sunlight is constantly changing. On the one hand, this
dynamic nature of sunlight has a positive influence on
the experience and feelings of wellbeing of individuals.
On the other, however, an excess of daylight and sunlight
can also cause visual discomfort, for instance, when
sunlight directly hits the computer screen.
A proper balance between the amount of daylight
that enters the room and the possibility of blocking
sunlight and daylight is therefore important for a visually
comfortable workplace. 614
Options for control
By giving occupants access to options for control of the
indoor climate, they can adjust it to their own needs. In
this context we are dealing with control of the amount of
Research shows that it is especially the “perception of
control” that has a significant impact on the level of
satisfaction of occupants. 615 Access to effective means
of controlling the indoor environment thus contributes to
the satisfaction of building occupants. 616
Noise
High noise levels of the electric motor of the solar or
daylight shading may give rise to noise complaints. Since
noise is only produced when the system is used, the
duration of the noise is limited. When the productivity effect
of increased noise is multiplied by the duration of the noise,
the overall productivity effect of installation noises will be
minimal. This aspect has therefore not been researched
in the literature studies. It is, nevertheless, important that
the noise level is not perceived as bothersome, so that the
solar shading and daylight shading systems may be used
as desired without troubling co-workers.
81

Approach
Literature review model
This literature review examines the influence that indoor
environment parameters have on productivity (figure 6.2).
First, the effect on productivity was considered,
measured by work performance or productivity tests
(objective indicators of productivity). If there was no
or insufficient literature available, the findings on
underlying subjective measures were reported, which
may serve as a productivity indicator.
Literature review approach
Scientific papers were the basis of creating an overview
of current insights in the effects of selected indoor
environment factors. Google Scholar was used to search
for studies on the relation between indoor environment
parameters and productivity. The following search terms
were used, in this order:
- In title: indoor environment parameter
+ “productivity” or “performance”.
- In title: underlying indoor environment
parameter + “productivity” or “performance”.
- In title: indoor environment parameter
+ productivity indicator.
- In paper: indoor environment parameter
+ “productivity” or “performance”.
Depending on availability and usefulness of the papers
found for the first search term, a new search was either
executed or not.
This was repeated for all selected indoor environment
parameters. In addition, literature was used that
had been collated in previous (research) projects in
bba binnenmilieu's database and relevant literature
references in documentation reviewed.
An overview of the findings in the selected papers was
collated into a matrix. This matrix includes the following
data of all studies:
- reference (authors, year, title, journal);
- indoor environment parameter(s) researched;
- productivity metric used;
- baseline scenario;
- intervention scenario;
- effect size;
- field study/lab study;
- reliability of results (significance, number of
participants, study design, notes).
The matrix was used to map the effect on productivity,
if any, in an assumed baseline scenario and intervention
scenario. For each study the condition which was present
when participants performed optimally was assigned
the value 1.
Subsequently, the relative decrease in performance
was calculated for the other conditions. When one study
reported several result metrics (same exposure and
same participants) these metrics were averaged and
non-significant results were included as 'no effect’.
On the basis of the studies found and in the case
of continuous variables, the median of the relative
productivity scores was plotted against the relevant
parameter. To understand the distribution of the data, we
also show the range of 50% of the metrics (P25-P75) and
90% (P5-P95) of the metrics.
82

Environmental factors
Parameters
Effect on building occupant
Overheating
Heat radiation &
radiation asymmetry
Temperature
Thermal sensation
Productivity
Alertness
work productivity
or productivity tests
(objective)
Daylight
Daylight luminance
Self-reported productivity
View
Quality of view
Concentration
underlying
subjective productivity
indicators
Glare from daylight
and direct sunlight
Level of glare
Visual comfort
Satisfaction
Options for control
Perception of control
Controls available
Absenteeism
Figure 6.2: Model with summary of indoor environment parameters and possible impact on productivity of office staff.
The relations in this chart were examined in this literature review.
83

84

85

Productivity effects
Temperature
Several studies examined the impact of high
temperatures on productivity. In 2006, Seppänen et al.
examined the effects in a review of the current literature
on the relation between temperature and productivity.
They found a total of 24 studies (both field and lab
studies) that they used to chart this relation (see figure
6.3). This research shows that productivity is highest
between 20 and 23°C. If temperatures increase further,
productivity decreases by 0.6 to 1.7% for every °C
temperature increase. The authors posited the following
formula for the relation between operative temperature
(T) and productivity (P): P = 0.16475*T - 0.00583*T2
+ 0.00006*T3 – 0.46853. We see that at an operative
temperature of 30°C, productivity decreases by an
average of 10%. A more recent review from 2012, taking
into consideration all indoor environmental factors,
confirms the negative effect of high temperatures on
productivity. This review concludes that excessive
temperatures lead to an annual productivity loss of 1.2
to 1.9% (Oseland & Burton (2012)). Weighing factors were
included for the activities that had to be performed and
the expected room temperature.
There are further publications, not yet included in the
formula posited by Seppänen, that report on studies
of the relation between temperature and productivity.
For instance, Kosonen & Tan demonstrated a relation
between environmental temperature and productivity
based on several studies by Wyon. A distinction was
made in this study between the activities of thinking
(-30% at 27°C) and typing (-33% at 27°C) compared to
21°C. In 2004, Witterseh et al. examined the impact of
both temperature (22, 26 and 30°C) and noise levels (35
and 55 dB) on the productivity of 30 subjects in a lab.
Out of the 5 productivity metrics examined, 2 showed a
negative effect from a higher temperature on the score
(16 to 26% worse scores).
Figure 6.3:
Relation between performance
and indoor operative temperature
according to the review of
Seppänen et al. (2006a, 2006b); the
(centre) line, "composite weighted",
is guiding in this report.
.8
.85
.95
.9
1
Composite weighted
Sample size weighted
Unweighted
15 20 25 30 35
Temperature [°C]
86

Subjects also reported that they found it more difficult to
concentrate at increased temperatures.
More recently, also Lan et al.'s (2011) and Geng et
al.'s field study (2017) and Cui et al.'s lab study (2013)
demonstrated that the productivity of participants
decreased with higher temperatures. It should be noted
that in Cui et al.'s study the optimum temperature was
relatively high (between 24 and 26°C); this may be
related to the relatively light clothing of the subjects (0.7
clo) and the thermal sensation which was slightly above
neutral.
However, Tanabe et al.'s lab study (2015) did not find a
significant difference between productivity at 25.5 and
28.5°C, nor did Balazova et al.'s study (2008), which
examined this at 23 and 28°C. In the latter study the
subjects did report they experienced lower productivity
with the higher temperature (-12%). It is important to note
that in this study the subjects were allowed to adjust
their clothing as they saw fit, which might mean they
perceived the temperature as less hot.
The effects that were measured during the (objective)
productivity tests in the studies mentioned above were
plotted against the room temperature and combined into
one figure (figure 6.4). We can see here that the results of
Seppänen et al., are generally being confirmed and that
productivity decreases with temperatures exceeding 23°C.
Kosonen & Tan's analysis (2004) demonstrates
significantly greater effects on productivity than the
other studies. Charting the metrics of these studies
clearly shows that there is a large distribution of effect
sizes (especially the P5 value, figure 6.5). In 50% of
the studies the centre line (median) indicates that
productivity decreases by at least 10% at temperatures
exceeding 30°C relative to the baseline situation.
Relative productivity
1,00
0,95
0,90
0,85
0,80
0,75
Seppänen et al. (2006)
Balazova et al. (2008)
Witterseh et al. (2004)
Lan et al. (2011)
Kosonen & Tan (2004)
Tanabe et al. 2015
Cui et al. (2013)
Geng et al. (2017)
Figure 6.4:
Relation between room
temperature and objectively
measured productivity based on
the studies cited in the legend.
0,70
0,65
0,60
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
Room temperature [°C]
87

Importantly, these studies were largely conducted
in buildings featuring active climate control or in a
laboratory. We know from research by Nicol, Brager &
De Dear that in buildings with passive climate control
(windows that can be opened, no cooling) occupants
experience higher temperatures in the summer as
desirable. In short: thermal comfort may also be attained
at a higher temperature. As far as we know no research
into the effects of room temperature on productivity has
been conducted for these types of buildings, but possibly
productivity is highest with a slightly raised indoor
temperature in these conditions as well.
Thermal sensation
Following on from the above paragraph, the relation
between thermal sensation and productivity has also
been demonstrated in several studies. In addition to
temperature, it is clothing, heat and cold radiation and
air velocity that also impact on thermal sensation. Solar
shading and daylight shading play an important part here.
The relationship between thermal sensation and
productivity is explained below, based on several studies.
A few of the studies addressed the relation between
thermal sensation and productivity as well as the relation
between temperature and productivity: Cui et al. (2013),
Geng et al. (2017), Witterseh et al. (2004), Lan et al.
(2010), Tanabe et al. (2015) and Kosonen & Tan (2004).
Most of the studies examined the effect around the
neutral range up to the warmer range (PMV -1 to +2), with
measured effects of up to approximately 10%. One study
that deviates is the one by Kosonen & Tan (2004) that
shows an effect of up to -33%. Geng et al. (2017) examined
the entire range (-3 to +3). The effect in the warmer range
was shown to be slightly greater than in the cold range,
which matches the results of the other studies.
A number of other studies also investigated the effect of
thermal sensation on productivity based on field studies
(Jensen et al., 2009; Ye et al., 2005) and lab studies
(Roelofsen, 2001; Wyon, 1979; Te Kulve et al., 2017; Te
Kulve et al., 2018; Hu & Maeda 2019).
Relative productivity
1,00
0,95
0,90
0,85
0,80
0,75
P95
P75
Median
P25
P5
Figure 6.5:
Median, P5, P25, P75 and P95
of the calculated relation between
room temperature and objectively
measured productivity.
0,70
0,65
0,60
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
Room temperature [°C]
88

89

These studies all reported an effect of thermal sensation
on productivity and in the majority of the studies the
effect turned out to be greatest in the hot range (-10%).
These studies are summarised in figure 6.6.
They examined this in an office with 200 office staff and
in a call centre (100 staff) (figure 6.8). The decrease in
productivity was up to 4.5% in conditions without daylight
or a view.
In order to represent the distribution of the results of the
various studies, the metrics were plotted in one graphic
(figure 6.7). Two studies report a significantly greater
productivity effect than the others (> 20%); this is clearly
indicated by the P5 and P25 values, the relation of which
strongly fluctuates. From P50 onwards a more logical
course in the relation may be noted, showing a decrease
in productivity in both the cold and the hot range.
When a sensation of warmth was reported (PMV = 2),
the productivity decreased with at least 4% in 50% of
the studies.
Daylight luminance and view
Daylight can be used as an alternative for artificial
lighting, offering a positive effect on energy consumption
but also on satisfaction regarding the amount of light
in the workplace (Newsham et al. 2009). Boyce et al.
(2003) concluded that daylight per se does not directly
contribute to higher productivity, but a visually welldesigned
environment does, and this is generally easier
to achieve when daylight is present. Day et al. noticed a
correlation between worker satisfaction about daylight in
the room and self-reported productivity.
The effect of the amount of daylight on objectively
measured productivity has only been found in one
study. Heschon Mahone's study (2003) demonstrates
that office workers perform better in workplaces
with ample daylight.
Several studies were found that examined the impact of
both the presence or absence of daylight and views.
A field study by Figueiro et al. (2002) demonstrated that
in an office with windows, office workers spend more
time on average on computer tasks (30% of the time)
compared to office workers in a windowless office (26%
of the time). Office workers who have their desk close to
the window spend less time chatting (5.8% vs. 7.9% of
the time) and being on the phone (2.0% vs. 3.7% of the
time). A field study by Jamrozik et al. (2019) compared
three different systems of daylight shading and glare
prevention: manual motorised “mesh shades”, automatic
tinting of glazing (with manual overrule option) and a
situation without daylight or view.
The productivity in the situation without daylight and
view was approximately 2% lower. A summary of these
findings appears in figure 6.9. The median of these
studies is a productivity decrease of 3% when there is no
daylight or view in the room.
It is noteworthy that a view of plants in a room may
positively impact productivity as well, according to
a lab study by Sanchez et al. (2018). In the morning,
participants were more productive if there were plants
present in the room than if there were no plants. Finally,
a field study demonstrated a correlation between the
quality of the light and the view, and absenteeism
(Elzeyadi (2011)).
90

Relative productivity
1,00
0,95
0,90
0,85
0,80
0,75
0,70
0,65
Cui et al. (2013)
Ye et al. (2005)
Geng et al. (2017)
Witterseh et al. (2004)
Lan et al. (2010)
Tanabe et al. 2015
Kosonen & Tan (2004)
Te Kulve et al. (2017)
Te Kulve et al. (2018)
Wyon et al. (2014)
Hu & Maeda (2019)
Roelofsen (2001)
Figure 6.6:
Correlation between thermal
sensation (PMV) and objectively
measured productivity based
on the studies cited in the legend.
0,60
Cold Cool Slightly cool Neutral Slightly warm Warm Hot
PMV
Relative productivity
1,00
0,95
0,90
0,85
0,80
0,75
P95
P75
Median
P25
P5
Figure 6.7:
Median, P5, P25, P75 and P95
of the calculated relation between
thermal sensation and objectively
measured productivity.
0,70
0,65
0,60
Cold Cool Slightly cool Neutral Slightly warm Warm Hot
PMV
Relative productivity
1,00
0,95
0,90
0,85
0,80
0,75
De Heschong
Mahone Group 2003
Average office study
De Heschong
Mahone Group 2003
Average call
centre study
Figure 6.8:
Daylight luminance
in relation to objectively
measured productivity.
0,70
0,65
0,60
0 200 400 600 800 1000 1200
Daylight luminance (lux)
91

Relative productivity
1,00
0,95
0,90
0,85
0,80
0,75
De Heschong Mahone Group 2003
Average office study
De Heschong Mahone Group 2003
Average call centre study
Jamrozik et al, 2020 Average
Figueiro et al 2002 time spent
on computer tasks
Figure 6.9:
Daylight and view
in relation to objectively
measured productivity.
0,70
Sanchez et al 2018 Average
0,65
Median of the studies
0,60
No daylight/
view
Automatic tinting
of windows
Daylight &
view
Daylight &
view
Daylight
Best view
Transparent daylight shading
Daylight
1,00
Figure 6.10:
Effect of the risk of glare
Relative productivity
0,95 Best view
No glare
0,90
No control
0,85
Frequent discomfort due to glare
0,80
Control available
0,75
0,89
Heschong Mahone Group
2003, Office study:
Digital Span Backwards
Long-term memory
Number search
Letter search
on various objectively
measured productivity tasks.
0,70
0,65
Landolt C
Average office study
0,60
No glare
Frequent discomfort due to glare
1,00
0,95
0,988
Boerstra (2015), air velocity
Figure 6.11:
The impact of having
control of the indoor
0,90
Leaman and Bordass (1999), lighting
environment on objectively
Relative productivity
0,85
0,80
0,75
Oseland& Burton (2012), temperature
Kroner & Stark-Martin (1994), temperature
Wyon (1996), temperature
Wyon (1974), temperature
measured productivity.
0,70
Boyce (2001), lighting
0,65
Lofness et al. (2003), temperature
0,60
No control
Control available
Median
92

Glare and visual comfort
Daylight and direct sunlight can create a high level of
luminance on the window surface. These high levels of
luminance can cause discomfort through glare (Shin et al.,
2012). Leaman and Bordass report glare as one of the
three main productivity killers. Results of a study that
included high luminance values with artificial lights also
demonstrate that performance decreases slightly (± 3%)
when these values are responsible for a decrease of
visual comfort because of glare (Osterhaus & Baily, 1992).
Conversely, light conditions that help create visual comfort
have a positive effect on performance (Veitch et al., 2008).
Only one publication was found that examined the impact of
daylight glare on productivity. The Heschong Mahone Group
examined the impact of the risk of glare on the performance
of 200 office workers (Heschong Mahone Group, 2003).
Researchers categorised the workplaces based on the
frequency of the likelihood of glare in the workplace,
ranging from never (0) to often (3).
On average, productivity scores were lower in workplaces
that had a higher likelihood of glare compared to
workplaces that had a low likelihood of glare. The
mean of these five resulting metrics constitutes a 11%
productivity decrease caused by glare (see figure 6.10).
Available and perceived control
As far as energy consumption is concerned, automatic
control of solar shading is most advantageous, but many
occupants prefer to be able to overrule such systems.
Furthermore, it appears that individuals have strongly
varying preferences for the exact moment in which to
activate solar shading (Velds, 2002). A field study by
Meerbeek et al. in 2014 showed that when presented with
the choice between manual or automatic control, the
majority (75%) of users opted for disabling the automatic
setting. In addition, results from a field study (Day et al.,
2019), conducted in three office buildings suggest that
having the option of controlling daylight/solar shading
is more important for a positive effect on self-reported
productivity than actually making use of it.
No studies were found in this literature review that
specifically quantified the effect of control of solar
shading or daylight shading on productivity. Two studies
did examine the impact of control of artificial light, but
found no significant effect on productivity (Boyce, 2000,
and Leaman and Bordass, 1999). There are, however,
multiple studies that demonstrate that the possibility of
exercising control over the temperature has a positive
effect on productivity (figure 6.11). The median of the
productivity effect is positioned here at +1.2%. The
Boerstra et al. field study (2016) is also in line with these
results; on the basis of research in nine office buildings,
a positive relation was found between perceived control
and self-reported productivity.
Another study by Boerstra et al. (2015), however, shows
the opposite effect; in this lab study participants showed
higher scores on productivity tests when they had no
control. This may be explained by the fact that the
settings that were chosen in the session “with control”
were also applied to the session “without control”. Having
control options available appears, therefore, to be
especially relevant if subjects/individuals are dissatisfied
with the environment.
93

When applying these findings to solar shading and
daylight shading, it is important to consider that different
people have different preferences concerning the indoor
environment and consequently prefer manual operation/
options to overrule the automatic setting. With regards
to daylight shading as well, this is not only important for
worker satisfaction but also for productivity. Individuals
who are more sensitive to light intensity appear to
perform less well on a reading task than people who do
not experience discomfort (Conlon, 1993). It follows that
this group will feel the need to apply daylight shading at
relatively lower light intensities.
Research shows, however, that manual operation in
summer is responsible for under-use of solar shading
aimed at counteracting the high heat load caused by
solar radiation (Wienold, 2007). It is essential, therefore,
to balance comfort with energy conservation.
In an effort to balance the option of control— and thus
occupant satisfaction—with energy performance,
research was conducted into displays that prompt the
user to activate solar shading (necessary to prevent
overheating), but which still allowed control for the user
(Meerbeek et al., 2016).
601. Valladares-Rend.n, L. G., Schmid, G., & Lo, S. L. (2017).
Review on energy savings by solar control techniques
and optimal building orientation for the strategic
placement of façade shading systems. Energy and
Buildings, 140, 458-479.
602. Sanati, L., & Utzinger, M. (2013). The effect of window
shading design on occupant use of blinds and electric
lighting. Building and Environment, 64, 67-76.
603. ES-SO Solar shading for low energy and healthy
buildings, 2018 accessible on: https://es-so.com/
information/publications.
604. De Grussa, Z., Andrews, D., Newton, E. J., Lowry, G. D.,
Chalk, A., & Bush, D. (2016, June). A Literature Review
Outlining the Importance of Blinds and Shutters as a
Sustainable Asset that has the Potential to enhance the
Productivity of Occupants in the UK. In Going North for
Sustainability Doctoral Workshop ARCOM/CHOBE.
London South Bank University.
605. Frontini, F., & Kuhn, T. E. (2012). The influence of various
internal blinds on thermal comfort: A new method for
calculating the mean radiant temperature in office
spaces. Energy and Buildings, 54, 527-533.
606. Meerbeek, B., Te Kulve, M., Gritti, T., Aarts, M., van Loenen,
E., & Aarts, E. (2014). Building automation and perceived
control: a field study on motorized exterior blinds in Dutch
offices. Building and Environment, 79, 66-77.
607 Fanger, P. O. (1970). Thermal comfort. Analysis
and applications in environmental engineering.
Thermal comfort. Analysis and applications in
environmental engineering.
608. NEN-EN ISO7730 – 2005 Ergonomics of the thermal
environment.
609. https://comfort.cbe.berkeley.edu/
610. Arbo-informatieblad AI24 Binnenmilieu (2017)
Thermisch binnenklimaat, luchtkwaliteit, geluid,
licht en uitzicht, SDU uitgevers.
611. Olesen, B. W., & Parsons, K. C. (2002). Introduction
to thermal comfort standards and to the proposed
new version of EN ISO 7730. Energy and buildings,
34(6), 537-548.
612. Marino, C., Nucara, A., & Pietrafesa, M. (2017).
Thermal comfort in indoor environment: Effect of the
solar radiation on the radiant temperature asymmetry.
Solar Energy, 144, 295-309.
613. NEN-EN ISO7730 – 2005 Ergonomics of the thermal
environment.
614. Arbo-informatieblad AI24 Binnenmilieu (2017)
Thermisch binnenklimaat, luchtkwaliteit, geluid,
licht en uitzicht, SDU uitgevers
615. Paciuk, M. T. (1990). The role of personal control
of the environment in thermal comfort and satisfaction
at the workplace.
616. Boerstra, A. C. (2016). Personal control over indoor
climate in offices (Doctoral dissertation, PhD thesis.
Eindhoven (NL): Eindhoven University of Technology.
Available via: http://repository. tue. nl/850541).
94

Conclusions
Based on the literature review, the productivity effects for the selected parameters were
summarised. The level of scientific support for the findings varies strongly per parameter.
The summary below shows the relative productivity effect for the best possible condition
(based on the studies reviewed) and a less than ideal situation (table 6.2). The last column
also shows the quality of the scientific support for the relation between the parameter and
the productivity effect.
Table 6.2: Summary of productivity effect per parameter.
Parameter Best possible (baseline) Less than ideal condition Calculated productivity
decrease
Quality of scientific
support#
Temperature 22°C 30°C -10% ***
Thermal sensation Neutral (PMV = 0) Warm (PMV = +2) -4% **
Amount of daylight 1100 lux No daylight -4.5% *
Daylight & view High-quality view & daylight No view or daylight -3% **
Glare No risk of glare High risk of glare -11% *
Visual discomfort No glare from artificial light Discomfort by glare from
artificial light
-3% *
Control of solar shading
& daylight shading
Control of amount of
daylight and sun entering
the room
Control of amount of
daylight and sun entering
the room
-1.2% *
Perceived control n.a. -
# Quality of support: *(very) poor, **average, ***good
The impact of thermal indoor climate on productivity has been researched extensively in the
past few decades. Generally, we may conclude that daylight and view are important factors
for satisfaction about the amount of light in the workplace, and that glare from direct daylight
and sunlight is considered to cause discomfort. There is only very limited research into the
degree to which these aspects impact on productivity and especially the size of the effect has
poor scientific support.
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7
QUANTIFYING PRODUCTIVITY GAINS FROM
THE USE OF SOLAR AND DAYLIGHT SHADING IN OFFICES
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PRODUCTIVITY EFFECTS MODEL
High quality daylight and solar shading systems contribute to a pleasant indoor environment.
When applied adequately in an office, these systems will impact on satisfaction of the indoor
environment. What's more, they will positively affect workforce productivity.
In this chapter we will quantify the relevant productivity effects of applying solar and daylight
shading in offices.
The quantification process has been integrated into
a mathematical model built in Excel. 701 This model,
yet to be refined and developed into a user-friendly
application (app), can be used by consultants to get
an indication of the potential productivity effect of an
intervention compared to baseline. This is done by asking
a number of key questions about the relevant office
building. Comparing this data with the estimated costs
of the intervention will provide insight into the return on
investment (ROI).
The model, hereafter referred to as the Somfy
Productivity Tool (SPT), is based on the findings of
the literature review in Chapter 6 and it enables us to
estimate productivity effects. 702 Based on the selected
five indoor environment parameters, we will first
establish at which locations workforce productivity is
affected by solar and daylight shading and after that we
will quantify the productivity gains that may be expected.
Firstly, for each indoor environment parameter, we
established which building properties were significant
in determining the impact of solar and daylight shading.
Secondly, we examined what the impact of applying
an intervention (solar and/or daylight shading) had on
the parameter and that result was compared with the
baseline situation (no shading systems). Finally, based
on the effect of the intervention on the indoor climate
and the productivity effects from the literature review,
an estimate was made of the average annual potential
for improvement for each parameter with solar and/or
daylight shading.
Figure 7.1 Steps to realise a model for calculating the productivity potential.
Relevant building characteristics:
- % glass surfaces in the façade.
- Reflective glazing installed.
- Distribution of workstations
across façades.
- Number of workstations
perpendicular to the façade.
- Number of people working in one space.
- Cooling system available.
- Presence at the workplace.
Impact on indoor environment
parameters:
- Air temperature.
- Heat radiation.
- Views and daylight.
- Glare.
- Individual control.
X
Productivity effect of indoor
environment parameters:
- Air temperature.
- Heat radiation.
- Views and daylight.
- Glare.
- Individual control.
=
Annual average
productivity potential
=
% productivity improvement
x
€ turnover
Intervention to be implemented:
- Daylight shading per façade.
- Solar shading per façade.
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The model calculates the average productivity potential
per year based on the intervention that is selected and
the characteristics of the building. In order to get an idea
of the extent to which the characteristics of a building
impact on the productivity potential, an estimate is made
of the impact of solar and daylight shading on the indoor
environment. Estimates for the potential productivity
effect were derived from research conducted by others.
The potential productivity effect is expressed in
percentages relative to the baseline situation. There are
two ways to calculate the ROI or the payback time of
the investment: the potential productivity effect can be
multiplied by the organisation's annual turnover or by
total staff costs. The method selected depends on the
type of organisation that occupies the building for which
the calculation is done.
The Somfy Productivity Tool was developed to provide
insight into the added value of implementing solar and
daylight shading in office buildings.
Starting points and building characteristics
I. Impact of indoor environment parameters:
productivity potential
Based on the results of the literature review, the following
productivity effects per parameter were used.
Air temperature
The literature review shows that productivity starts to
drop as temperatures increase. This effect starts from
a temperature of ± 23°C.
The productivity effect due to air temperature was
determined for each temperature interval as shown
in table 7.1.
Table 7.1: Assumptions regarding the productivity effect
of air temperature.
Temperature range
Productivity effect assumption
≥ 23°C 0%
24 < 26°C -0.8%
26 < 28°C -3.2%
28 < 30°C -6.40
30 < 32°C -10.5%
≥ 32°C -13.9%
Heat radiation
In addition to the influence of air temperature we have
also focused on the impact of heat radiation, i.e. influence
of the increase in the thermal sensation due to solar
radiation. Its impact on productivity was determined
based on the influence of solar radiation on the thermal
sensation in the PMV model, at a constant air temperature.
A one-point increase in the PMV (compared to neutral)
results in an estimated productivity effect of - 2%.
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Glare
Due to the limited number of studies about the impact
of glare on productivity, the average was taken between
the results of glare and visual comfort; -11% and -3%,
respectively. Since scientific support for this effect is
poor, and the value for glare very high, the potential
effect in the model was reduced by 50% as a matter of
precaution. This means that when glare is likely to occur,
a productivity reduction of 3.5% is applied.
Views and daylight
When workers cannot look out of a window or have no
daylight (due to the use of solar and/or daylight shading)
the productivity potential in the model decreases by 3%.
Individual control
When workers have the option of individual control
over the indoor environment it contributes to workplace
satisfaction and productivity. If a workplace offers full
individual control of solar and daylight shading systems
the model allows for a productivity effect of 1.2%.
II. Intervention to be installed and relevant
building characteristics
Three types of solar and daylight shading systems are
included in the model. They are defined as follows:
- Light shading – functional solar shading to be
applied to the inside of the window.
- Indoor sun shading – functional solar shading
that is applied to the inside of the window. It has
a textile layer of thin reflective aluminium on the
outward-facing side of the material.
- Solar shading – screens applied to the exterior
of the building directly onto the window (colours
according to NTA8800).
For the solar and light shading systems the LTA (light
transmittance factor) and g-values (solar transmittance
factor) were used as shown in table 7.2 below.
Table 7.2: Characteristics of interventions used with regular glazing and reflective glazing
(source of the values: NTA 8800: 2020 NL).
Intervention regular glass reflective glass
LTA g-value LTA g-value
No intervention (reference) 0.70 0.60 0.50 0.40
Daylight shading 0.12 0.45 0.12 0.30
Indoor solar shading 0.04 0.27 0.04 0.18
Solar shading (outdoor) 0.07 0.12 0.07 0.08
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In calculating the impact of solar shading and/or daylight
shading interventions on the indoor environment and the
productivity effect, the following building characteristics
and their influence are considered:
- Percentage of glass surfaces in the façade.
- Reflective glass installed per façade.
- Distribution of work spaces per façade.
- Depth of the work stations measured as the
distance to the window.
- The total number of persons working in a space.
- Cooling system in place.
- Presence of staff at the workplace.
For completeness - and as part of the model - we have
included a questionnaire related to this subject. See
Appendix 7.1 at the end of this chapter.
III. Average productivity effect per year
Based on the starting points described above, an
estimation per parameter is made of the impact the
intervention has on the indoor environment and the
estimated annual productivity effect that goes with
it. After all, the influences per parameter are simply
a snapshot, whereas the model should allow for the
average measured frequency over the year that a certain
condition occurs.
For each parameter the average productivity effect per
year due to the influence on the indoor environment is
calculated, with and without an intervention:
- PT: Average productivity effect per year
due to air temperature.
- PS: Average productivity effect per year
due to heat radiation.
- PU: Average productivity effect per year
due to view.
- PV: Average productivity effect per year
due to glare.
- PC: Average productivity effect per year
due to control.
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102

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Influence of solar and daylight shading on the
indoor environment and productivity
Air temperature
The impacts of the implemented intervention on air
temperature in the space were modelled using a
calculation of temperature overshoots in DYWAG (DGMR
software). 703 The difference in air temperatures generated
by the solar transmittance factor (g-value) in the baseline
scenario and in solar or daylight shading scenarios was
used as input for the productivity tool.
solar shading. Table 7.3 shows the percentages for the
southern façade (sample building).
The annual productivity effect per scenario was
subsequently calculated by multiplying the percentage
of the time by the productivity effect for the relevant
temperature interval (last row in table 7.3). The average
productivity effect per year for the sample building is
shown in table 7.4 for each façade and intervention.
For this purpose, a sample building was set up based on
the following starting points (for all the façades: north,
east, south, west): 704
- Reflective glazing installed per façade:
no reflective glass (ZTA value 0.6)
- Cooling system: top cooling.
- Percentage of glass surfaces in the façade:
50% glass (average).
For each orientation we modelled what percentage of
the (operational) time a certain temperature interval (see
table 7.3) would occur in the different scenarios: baseline;
with light shading; with indoor solar shading; with outdoor
Building factor:
Next, the separate and combined impact of different
building characteristics was modelled by creating different
variations of the same sample building. 705 For this purpose
the impact of the following aspects was examined:
- Percentage of glass used for the façade (low/
average/high): In buildings with façades
containing large glass surfaces, solar radiation
tends to have a greater impact on the air
temperature than in a building with relatively
little glass in its façade. The relative impact of
implementing solar shading in a building with
large glass surfaces will consequently be higher.
Table 7.3: Percentage of the time a temperature interval occurs in four different scenarios
(south-facing façade of sample building).
Temperature
range based on
TO calculation
% of the time Temperature
Baseline situation Daylight shading Indoor solar shading Outdoor solar shading
productivity effect
assumptio
23 °C 50% 59% 72% 78% 0%
24 < 26 °C 26% 22% 15% 14% -0.80%
26 < 28 °C 24% 19% 13% 8% -3.20%
28 < 30 °C 0% 0% 0% 0% -6.40%
30 < 32 °C 0% 0% 0% 0% -10.50%
≥32 °C 0% 0% 0% 0% -13.90%
Productivity
effect per year
-0,97% -0,78% -0,55% -0,38%
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- Reflective glazing installed in façade (yes/
no): Where reflective glazing is applied, a larger
proportion of solar radiation will be reflected,
ensuring less solar radiation impact on air
temperature than in a setting without reflective
glazing. The relative impact of implementing solar
shading in a building with reflective glass will
consequently be smaller.
- Cooling system (comprehensive cooling/ top
cooling/no active cooling): In a building with
comprehensive cooling the cooling capacity is such
that the indoor temperature is pleasant, even during
summer (point of departure in this model is max.
24°C). When a building has top cooling, it will offer
less capacity for cellular layouts. As the outdoor
temperature increases or in very sunny conditions,
the indoor temperature is more prone to follow the
outdoor temperature (point of departure in this
model is max. 26°C). In a building without cooling
the indoor temperature will increase even further
(depending on the use and characteristics of the
building). Consequently, installing solar shading in a
building without cooling has the greatest impact.
Solar shading can contribute to reduced energy consumption,
especially in buildings with comprehensive cooling solutions,
as less solar radiation will enter the building.
Based on the results of the different modelled
variants (adjustments relative to the sample model)
we established the average impact of each building
characteristic on the air temperature and the
corresponding productivity effect. For all building
characteristics an individual factor has been determined
for that purpose. The results of the sample building are
used as a starting point and multiplied by the factor(s) of
the characteristics that deviate from the sample building
(table 7.5). The factors that are applicable to the building
are multiplied, resulting in a “building factor”.
For example: a building with reflective glazing, top
cooling and 80% glass will get a building factor of 0.78 x 1
x 1.34 = 1.05. Using this “building factor” the productivity
potential of the intervention we want to implement is
applied to the building we want to study.
Table 7.4: Yearly-averaged productivity effect base
model (PT) for each façade for the reference situation
and the various interventions.
Table 7.5: Multiplication factors for the various
building characteristics.
North East South West
Baseline situation -0.47% -0.79% -0.97% -0.63%
Daylight shading -0.45% -0.69% -0.78% -0.58%
Indoor solar shading -0.44% -0.55% -0.55% -0.50%
Outdoor solar
shading
-0.42% -0.41% -0.38% -0.41%
Glazing Cooling % glass Reference
Without reflective glass Top cooling 50% glass 1 (reference)
With reflective glass 0.78
Without cooling 2.11
With cooling 0.40
25% glass 0.80
80% glass 1.34
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Productivity effect:
The average productivity potential per year of
implementing the intervention can then be determined
for each façade by calculating the difference between
the loss of productivity in the baseline situation (PT VB
baseline situation) and the post intervention loss (PT VB
intervention) (table 7.4). Using the values from table 7.4
will give insight into a building's productivity potential,
provided its characteristics match those of the sample
building. When a building has characteristics that deviate
from the sample, the numbers per façade should be
multiplied by the building factor based on table 7.5. The
productivity potential per façade due to air temperature
can be expressed using the following formula:
ΔPT = (PT VB intervention – PT VB baseline) * building factor
Heat radiation
As mentioned above, solar radiation can lead to an
increase in air temperature. In addition, heat radiation
contributes to a temperature that is perceived as hotter
(at a consistent air temperature the sun will feel warmer
than without direct sunshine).
How this heat radiation affects productivity is also
considered in the productivity tool by expressing its
effect on thermal sensation (assuming a consistent air
temperature).
The predicted thermal sensation due to solar radiation
is explored using the “PMV thermal comfort model”. In
the model, the operational temperature is determined by
heat radiation and air temperature. If we want to examine
heat radiation only, we assume that the environmental
temperature remains consistent. The contribution of
heat radiation is calculated as the difference in radiation
temperature resulting from solar radiation and air
temperature (ΔMRT). Solar radiation can be calculated
using the parameters in table 7.6.
In this scenario the first 3 parameters are assumed to
be constant. Parameters 4 and 5 are dependent on the
building characteristics (distance from work station to
the façade and glass surface). The further away from
the façade that desks are positioned (distance between
workstation and façade) the greater the impact of heat
radiation on the thermal sensation decreases.
Table 7.6: Parameters needed to calculate the radiation temperature due to solar radiation using the value
or range applied in the productivity tool (ASHRAE-55). 706
Heat radiation parameters Value/range used Subject to building characteristics Source
1) Absorption of shortwave radiation 0.7 Constant Default – ASHRAE-55
2) Solar altitude 38° Constant Lat. 52° N (21 March and 21 Sept)
3) Corner of façade relative to person 90° Constant ASHRAE-55 (perpendicular to façade)
4) Sky is partly visible to occupant 0.1 to 0.3 Distance to glass surface of façade ASHRAE-55
5) Part of body exposed to sunlight 0.3 to 0.7 Glass surface ASHRAE-55
6) Solar radiation 141 to 650 W/m² Orientation of façade Table average solar radiation
7) Solar transmission g-value Glazing intervention Table 2 (g-values)
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The impact is also smaller with fewer glass surfaces because they limit exposure to the
sun. Tables 7. (parameter 4) and 7.8 (parameter 5) show the values that should be applied
for this purpose based on ASHRAE-55.
Table 7.7: Parameter 4: part of the sky visible to the occupant based on ASHRAE-55,
depending on percentage of glass surface in the façade and distance between the
workstations and the window.
Max. 2 desks
At least 3 desks
Low use of glass < 30% 0.2 0.1
Average 30 to 60% 0.25 0.15
High use of glass > 60% 0.3 0.2
Table 7.8: Parameter 5: part of the body exposed to sunlight based on ASHRAE-55,
depending on percentage of glass surface in the façade.
Exposure [-]
Low use of glass < 30% 0.3
Average 30 to 60% 0.5
High use of glass > 60% 0.7
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Building factor:
Based on the aforementioned seven parameters, the ΔMRT can be calculated in an
online PMV calculator (Predicted Mean Vote calculator). 707 Given a constant value for
solar radiation and solar transmission this calculator can be used to calculate the ΔMRT
for any six combinations from tables 7.7 and 7.8. On this basis, the five parameters can
be combined into a building factor that can be calculated as follows (at a given solar
radiation and g-value):
Building factor [°C/ (W/m2)] = ΔMRT [°C] / (solar radiation *10-2 [W/m2] * g-value)
The building factor in this model can take on six values, as shown in table 7.9 below
(depending on building characteristics). The ΔMRT is dependent on this factor, solar
radiation, and the g-value. The g-value in turn affects solar transmission as well as a
property of the glazing and the intervention (such as displayed in table 7.1).
Table 7.9: Building factor based on building characteristics
to calculate the ΔMRT in °C/(W/m²).
Max. 2 desks
At least 3 desks
Low use of glass < 30% 1.8 1.3
Average 30 to 60% 2.6 2.1
High use of glass > 60% 3.4 3
The amount of solar radiation is dependent on the orientation of the façade and the season (table
7.10) and is determined by the total monthly average of direct solar radiation (NTA 8800:2020 nl)
corrected for the number of sunshine hours per month (KNMI) and the average per season.
Table 7.10: Average intensity of solar radiation in W/m² during sunny conditions
per façade and season.
North East South West
Winter 141 257 650 257
Spring 208 425 530 368
Summer 237 374 427 435
Autumn 179 324 643 330
Based on the data above, the ΔMRT (heat radiation) for the baseline situation and
the intervention per season and façade can be calculated. The difference between
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the baseline and the intervention situation is caused by the difference in the solar
transmission factor (g-value).
ΔMRT [°C] = building factor (table 7.9) * solar radiation *10-2 (table 7.10) * g-value (table 7.2)
Before the heat radiation can be translated into a productivity effect, the PMV (thermal
sensation) should be calculated. The input parameters for the PMV model can be found
in table 7.11. The “clothing insulation” and “air temperature” parameters obviously differ
per season. Using the parameters below and the calculated heat radiation (per façade
and for the baseline as well as intervention situation) we can then calculate the average
thermal sensation per season and façade and for both the baseline and intervention
scenarios. Calculation of the PMV value is done in accordance with NEN-EN-ISO 7730. 708
Table 7.11: Input parameters for the PMV model per season.
Winter Spring Summer Autumn
Air temperature [°C] Ta 22 23 24.5 23
Delta radiation temperature Δ MRT ΔMRTWinter ΔMRTSpring ΔMRTSummer ΔMRTAutumn
Operational temperature [°C] Top Ta + ΔMRT/2 Ta + ΔMRT/2 Ta + ΔMRT/2 Ta + ΔMRT/2
Humidity [%] RV 50 50 05 50
Air velocity [m/s] V 0.1 0.1 0.1 0.1
Activity [MET] A 1.1 1.1 1.1 1.1
Insulation value of clothing [clo]; I 1 0.8 0.6 0.8
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Productivity effect:
The estimated productivity effect increase of one point on the PMV scale is -2.0%. The
difference between the PMV value in the baseline situation and post intervention should
therefore be multiplied by -2.0% in order to estimate the productivity effect per façade
and season (when the sun is shining).
The impact of heat radiation on the perceived temperature is only applicable when
the sun is shining. In order to calculate the average impact during the season for each
façade, the productivity effect per season should be multiplied by the percentage of
sunshine time (table 7.12). Then the average value per year can be calculated for each
façade using the seasonal average.
ΔPS = (PMV intervention – PMV reference) * -2% * % sunshine time
Table 7.12: Percentage of sunshine time per season.
Sunshine time
Winter 18%
Spring 47%
Summer 55%
Autumn 29%
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View and daylight
In order to assess the productivity effect of views and daylight for each façade we
estimated the probability of occupants with no or limited views, compared to a situation
where the building has no solar or daylight shading facilities, and where no reflective
glass has been applied.
Building factor:
In general, the availability of views and daylight will depend on the following building
characteristics:
- The percentage of glass used for the façade (low/average/high); the more glass is
used, the greater the view and the amount of daylight.
- The distance between the desks and the façade (max. 2 desks/at least 3 desks);
the closer the position of the work station near the façade, the greater the view and
the amount of daylight.
Consequently, for the baseline situation (no solar or light shading) there are six variants
for which the availability of view and the amount of daylight can be determined (building
factor). The point of departure here is that the available view is reduced by 1/6 as
the percentage of glass decreases (per category) and as the distance to the window
increases, see table 7.13 (1 = most view and daylight).
Table 7.13: 'Views and daylight' building factor based on the building characteristics.
Max. 2 desks
At least 3 desks
Low use of glass < 30% 0.67 0.56
Average 30 to 60% 0.83 0.69
High use of glass > 60% 1.00 0.83
Light transmission factor (LTA)
The implementation of solar and light shading leads to a decrease in the available views
and daylight. In the model, this effect is linked to the light transmission factor (LTA value).
The LTA value of solar and light shading is relevant in sunny conditions. In cases where
buildings are fitted out with both solar and light shading we assume that each system is
used during 50% of the time. Therefore, to calculate the average annual effect we use the
mean of the LTA value.
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The implementation of reflective glass also leads to a reduction in the available view and
daylight due to a lower LTA value. This value is applicable where no daylight and/or solar
light shading is used. The maximum LTA value in this model is 0,7 (non-reflective glazing
(see table 7.1)). Productivity loss for the baseline situation is calculated relative to this value.
Amount of time the façade is exposed to sun
The decrease in availability of views and amount of daylight apply when solar and daylight
shading are being used. Here we assume that the reduction of the available view and
amount of daylight correspond with the use of these systems aimed at preventing direct
solar radiation and glare. The percentage of time that solar light and/or daylight shading
systems are actively used should therefore match the percentages described in table 7.14.
Productivity effect:
Based on the literature review, the potential productivity loss resulting from reduced
views and daylight is estimated at -3.0%. The productivity loss with a solar and/or
daylight shading scenario compared to baseline (delta) is then calculated for each
façade using the following formula:
ΔPU = ΔLTA * -3% * building factor (table 7.15) * time façade exposed to sun (table 7.14)
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Glare
In order to assess the productivity effect of glare for each façade, we estimate what the
yearly averaged probability of glare is per façade without light shading or solar shading
(baseline).
Building factor:
In the model we assume that the probability of glare is dependent on the following
building characteristics:
- The percentage of glass used in the façade (low/average/high); the more glass is used,
the greater the probability that solar radiation entering the workplace can be annoying.
- The distance of desks to the façade (max. 2 desks/at least 3 desks); the closer the
position of a workstation near the façade the greater the probability that the solar
radiation entering the workstation is perceived as annoying.
Consequently, for the baseline situation (no solar or light shading) there are six variants for which
the probability of glare has been determined (building factor). The point of departure is that the
probability of glare is reduced by 1/6 as the percentage of glass decreases (per category) and as
the distance to the window increases, see table 7.14 (1 = highest probability of glare).
Table 7.14: 'Glare' building factor based on the building characteristics.
Max. 2 desks
At least 3 desks
Low use of glass < 30% 0.67 0.56
Average 30 to 60% 0.83 0.69
High use of glass > 60% 1.00 0.83
We have also assessed what percentage of the time glare could occur per façade. For
glare to happen two criteria must be met:
- the sun is shining at that moment (% of hours of daylight of the total amount of
sunshine per month);
- the position of the sun is such that solar radiation is at least 150 W/m2 (suppose
the sun is shining: the percentage of the time the façade is exposed to sunshine).
Using data from the KNMI, we have established the average percentage of the hours of
709, 710
sunshine per month compared to the average length of daylight in that particular month.
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114

We have also examined how many hours of the day each façade is likely to be exposed
to direct solar radiation. 711 Again, the percentage of time was determined based on direct
sunlight entering the workplace compared with the average length of daylight in that
month. Finally, these two percentages were multiplied to determine the percentage of
time the façade is exposed to direct sunlight per month.
Table 7.15: Percentage of time of monthly exposure of façade to direct sunlight.
% of time of sunlight on façade multiplied by the probability of sunny weather
North East South West
Jan 0% 6% 20% 6%
Feb 0% 10% 22% 9%
March 0% 13% 22% 11%
April 1% 14% 28% 15%
May 2% 12% 30% 16%
June 2% 11% 29% 16%
July 2% 12% 27% 15%
Aug 1% 13% 28% 14%
Sep 0% 14% 24% 12%
Oct 0% 11% 24% 10%
Nov 0% 6% 18% 5%
Dec 0% 3% 16% 3%
Mean 1% 10% 24% 11%
Productivity effect:
Based on the literature review, the potential productivity loss resulting from glare is
estimated at -3.5%. For the baseline situation the average productivity effect per year
resulting from glare can be calculated, per façade, using the following formula:
PV baseline = -3.5% * building factor (table 7.13) * hours of sun on façade (table 7.14)
In a situation where indoor solar shading and/or daylight shading was installed, the
assumption is that the devices will prevent 95% of glare by sunlight or daylight. The
productivity gain from the use of solar or daylight shading per façade would then be:
ΔPV = - PV baseline * 95%
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Possibilities for individual control
Finally, the impact of individual control of the indoor climate is also included in the
productivity potential. The possibilities for individual control by having solar and/or
daylight shading in place with manual or automatic operation depends on:
- the number of staff working in the space (building layout factor);
- the availability of solar and/or daylight shading;
- the percentage of the time the façade is exposed to sunlight, giving occupants
the possibility to control the indoor environment by using the solar and/or daylight
shading systems that are in place (table 7.15).
Building layout factor
The building layout factor is based on the number of staff working together in a space.
The more individuals you have working in one single space, the less individual control
they have (consensus required). In this model this factor can take on 4 values, as shown
in table 7.16, depending on the number of staff working in one single space.
Table 7.16: Layout factor for the degree of control experienced
based on the number of staff in one single space.
Number of persons in one office space
Factor
1 person 1
2 to 3 persons 0.8
4 to 8 persons 0.65
> 8 persons (large open-plan office spaces) 0.5
Façade exposed to sun
The possibilities for control are the greatest when both light shading and solar shading
are provided. When only one of either is available, the potential for individual control will
be somewhat reduced. In the formula the starting points for loss of productivity as a
result of the intervention are applied as described in table 7.17.
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Table 7.17: Impact of applied intervention on loss of productivity
due to possibilities of individual control
Availability of solar and daylight shading 0
Factor
Availability of solar or daylight shading 0.25
No solar or daylight shading 1.0
Productivity effect:
Based on the literature review, the potential productivity loss resulting from lack of
control of the indoor climate is -1,2%. Thus, the productivity loss when implementing solar
and/or daylight shading is calculated for each façade using the following formula:
ΔPC = intervention (table 7.17) * -1,2% * layout factor (table 7.16) * time sun on façade (table 7.14)
701. Somfy Productiviteitstool DEF” (2020, October 20) .
702. Report: “BM20204466F1 bba literatuuronderzoek
productiviteit – Somfy” (2020, June 17).
703. https//dgmrsoftware.nl/producten/bouw-energieenbrand/energieadvies/dywag/.
704. See Appendix 2 for the assumptions used in the
calculation.
705. See Appendix 2 for an overview of the various scenarios
that were modelled.
706. Arens et al, (2018) Sunlight and indoor thermal comfort-
Update to Standard 55, ASHRAE Journal July 2018.
707. https://comfort.cbe.berkeley.edu/.
708. Macro in excel: developer tab, visual basic.
709. https://www.knmi.nl/kennis-en-datacentrum/uitleg/
zonneschijn.
710. https://Projects.knmi.nl/klimatologie/uurgegevens/
selectie.cgi (de Bilt, 2019).
711. http://wiki.bk.tudelft.nl/mw_bk-wiki/images/6/64/
Intensiteit-directe-zonnestraling-voor-verticale-vlakken.
jpg Tussen 7- 19 >150 W/m2 in uren 52° N.B. verticale
vlakken en T=4 (stedelijk gebied).
117

118

7 .1
APPENDIX | QUESTIONNAIRE
119

To enable calculation of the productivity potential in a building the following questions
should be answered in the tool. The questions are divided into several categories:
- Building characteristics
- Productivity effect value
- Intervention to be applied
- Investment
I. Building characteristics
1. What is (roughly) the percentage of glass surfaces in the façade for which solar
and/or daylight shading is installed?
a. Low use of glass < 30%
b. Average 30 to 60%
c. High use of glass > 60%
2. Has reflective glazing been applied for the building?
North: yes no
East: yes no
South: yes no
West: yes no
3. What is the (global) division of workstations across each façade?
North: %
East: %
South: %
West: %
120

4. How many desks are positioned next to each other, perpendicular to one façade?
a. 2 desks
b. At least 3 desks
5. How many people typically work together in one single space?
a. 1 person
b. 2 to 3 persons
c. 4 to 8 persons
d. > 8 persons (large open-plan spaces)
6. Are there any cooling facilities in the building?
a. Cooling is available
b. Only top-cooling
c. No cooling
7. What percentage of the time is work (generating the turnover) effectively
carried out at the work place in the building?
% of the time that work is carried out at the office workplace
(not at home or outside of the workplace)
II. Productivity effect value
8. Does the vast majority (> 90%) of the staff work at the office?
yes
no
If question 8 is “No” continue with question 9a. If question 8 is “Yes” continue with question 9.
9. How many FTEs do you employ? FTEs
After question 9 continue with question 10
9a. How many FTEs do you employ in total? FTEs
9b. Of these, what percentage consists of office workers? %
121

For the following questions please enter the data for the organisation as a whole
10. Do the staff work for a company or organisation operating on a profit-making basis
(e.g.: SMEs “yes” and government institution “no”)?
yes no If question 10 is “No” continue with question 12.
If question 10 is “Yes” continue with question 11.
11. What is the annual turnover of the applicable department/organisation?
in millions of euros
Default value: 350,000 euro/FTE
12. What are the total annual costs per FTE? (Determine the total annual expenses and
divide that number by the number of FTEs (labour costs, accommodation costs, etc.))
in euros Default value: 75,000 euro/FTE
III. Intervention to be applied
13. Apply daylight shading to:
North: yes no
East: yes no
South: yes no
West: yes no
14. Apply solar shading to:
North: yes, outdoor solar shading yes, indoor solar shading no
East: yes, outdoor solar shading yes, indoor solar shading no
South: yes, outdoor solar shading yes, indoor solar shading no
West: yes, outdoor solar shading yes, indoor solar shading no
15. Apply individual control and automatic control to solar shading.
122

IV. Investment
16. What is the total surface of glass per façade?
North: m 2
East: m 2
South: m 2
West: m 2
17. What are the costs per m2
Daylight shading €/m 2
Indoor solar shading €/m 2
Outdoor solar shading €/m 2
123

124
7 .2
APPENDIX | CALCULATING TEMPERATURE OVERSHOOTS

Below we will list the major elements for temperature overshoot calculations.
Starting point is a building with a typical building mass (see Building construction).
Next, we have explored what the effect is of:
- the percentage of glass used in the façade;
- the use of reflective glass versus regular glass;
- the availability of cooling.
General points for calculation:
Climatic year: NEN5060-1% (2018)
Usage time/hours on energy meter counter: 12 hours per day, 5 days a week
(1st January through 31st December)
Building construction
- Inner wall: 2x plasterboard 12 mm - insulation 100 mm (R-value 2.13 (m2.K)/W)
- Outer wall: Masonry – cavity – 110 PUR insulation – plasterboard (R-value 4.755 (m2.K)/W)
- Window (glass + frame): 25% frame and 75% glass (U-value 1.1 W/( m2.K) – ZTA value 0.4 or 0.6)
- Floor/ceiling: 50 screed flooring – 200 mm concrete (R-value 0.127 (m2.K)/W)
Ventilation
- Basic ventilation: 150 m3/hour from 07.00 am to 07.00 pm (50 m3/hour per person)
- Air infiltration: 0.05 * spatial volume
- Natural ventilation: 288 m3/hour
• Open windows at indoor temperatures > 24ºC
• Close windows at outdoor temperatures > 26ºC
• Close windows at outdoor temperatures < 12ºC
• Close windows at indoor temperatures < 20ºC
• Close windows at wind speeds from 3.0 m/s
125

Solar shading
Characteristics
Table 7.2.1: Characteristics of interventions applied with “regular” glazing and reflective glazing
Daylight shading or solar shading type Fc-value g-value of regular glass g-value of reflective glass
Daylight shading 0.75 0.45 0.30
Indoor solar shading 0.45 0.27 0.18
Outdoor solar shading 0.20 0.12 0.08
Outdoor solar shading
- Automatic solar shading control
- Down at 150 W/m2
- Up at 150 W/m2
Indoor solar shading
- Automatic solar shading control
- Down at 150 W/m2
- Up at 150 W/m2
- Convection factor when down 0.20
Internal heat load
- Persons (80 watts per person)
- 3 persons per office
• 20% 07.00 am to 09.00 am
• 80% 09.00 am to 05.00 pm
• 20% 05.00 pm to 07.00 pm
- Laptop (100 watts)
• 20% 07.00 am to 09.00 am
• 100% 09.00 am to 05.00 pm
• 20% 05.00 pm to 07.00 pm
- Lighting (5 W/m2)
126

Cooling
- Comprehensive cooling (max. 24 degrees (95%) of the time in the basic scenario; overshoot
hours calculated using that capacity), no setpoint dependent on outdoor temperature
- Top-cooling (max. 26 degrees (95%) of the time in the basic scenario; overshoot hours
calculated using that capacity): ISSO74 class B active cooling
Table 7.2.2: Office cooling capacity entered per orientation.
Glass ZTA value* of glass 0.6
Max. 26ºC office
Glass percentage (%) 25 50 85
South 1418 2012 2879
West 1294 1855 2812
North 997 1224 1539
East 1244 1865 2778
Glass ZTA value* of glass 0.4
Max. 26ºC office
Glass percentage (%) 25 50 85
South 1225 1677 2209
West 1138 1530 2111
North 923 1129 1323
East 1091 1496 2098
Glass ZTA value* of glass 0.6
Max. 24ºC office
Glass percentage (%) 50
South 2230
West 2063
North 1443
East 2065
*g-value measured at 45° angle
127

Heating
Heating of air - unlimited capacity
Model
North 0.0º
XX000
X0000
North
East
West
South
X0000 X0000
X0000
X0000
X0000
Façade containing 25% glass
Façade containing 50% glass
128

Scenarios
The following scenarios were fully modelled:
- No reflective glazing No cooling Average use of glass %
- No reflective glazing Top-cooling Low use of glass
- No reflective glazing Top-cooling Average use of glass %
- No reflective glazing Top-cooling High use of glass
- No reflective glazing Comprehensive cooling Average use of glass %
- Reflective glazing Top-cooling Low use of glass
- Reflective glazing Top-cooling Low use of glass
- Reflective glazing Top-cooling Low use of glass
Productivity effect of sample building
Table 7.2.3: Average annual productivity effect of sample building (PT) per façade
for the reference situation (baseline) and the various interventions.
North East South West
Reference -0.47% -0.79% -0.97% -0.63%
Daylight shading -0.45% -0.69% -0.78% -0.58%
Indoor solar shading -0.44% -0.55% -0.55% -0.50%
Outdoor solar shading -0.42% -0.41% -0.38% -0.41%
129

130

8
DETERMINING THE AVERAGE ANNUAL
PRODUCTIVITY EFFECT IN OFFICES
131

PRODUCTIVITY EFFECT PER PARAMETER
Based on the calculations we can estimate the theoretical productivity effect that an intervention
produces for each indoor environment parameter (Px). The productivity effects described in chapter
3 are dependent on the orientation of façades. To determine the total productivity effect for an
intervention in a building we need to work out the weighted mean of the effect per façade. The
potential average productivity effect per year of the four façades must, therefore, be multiplied by
the distribution of staff across the façades (% of the workers per façade (WP)):
Average annual productivity effect = %WPnorth*Px north + %WPeast*Px east + %WPsouth*Px south + %WPwest*Px wes
Total productivity effect
The total productivity potential of the building can be
calculated by working out the total of the individual
productivity effects (parameters). Since a reduction in
productivity by one of the parameters may affect the
relative impact of the other parameters, a correction
should be applied here. This correction is an assumption
based on an article by Oseland & Barton (2012), in
which the results of three multiple factor studies were
compared.801 The resulting equation is:
Ptotal = P1 +⅔ P2 + ⅓ P3
This explains why reduction is not applied for
the views factor.
- The reductions in productivity due to heat
radiation and change of air temperature
are tallied without correction because both
factors have an impact on the temperature
experienced by occupants. The literature review
demonstrates that extreme values produce an
increased productivity reduction at least equal
to the sum (PTS = PT + PS).
- The weighing factors are applied in order of effect
From this formula we can derive that the productivity
loss resulting from the first parameter is fully included,
while the second parameter counts for 2/3 and the
third parameter for 1/3. In the Somfy Productivity Tool
the following standard assumptions were applied for
calculating the simultaneity of productivity effects.
- When compared to the baseline situation, the
reduction in productivity caused by a lack of
views due to solar/light shading will never occur
simultaneously with a reduction in productivity
due to temperature, radiant heat, glare or control
in a solar/light shading scenario.
size, i.e. the greatest reduction factor is applied to
the smallest productivity effect.
For example: If PTS > PV > PC is true for a given
situation, the result will be:
Ptotal = PU + PTS + ⅔ PV + ⅓ PC
This total value should subsequently be multiplied by the
% of the time that staff carry out their activities at the
office workplace (i.e. not outside the office or at home).
The intervention has obviously no effect on the activities
performed outside of the workplace.
132

Ppotential total = Ptotal * % of activities at the office workplace
Productivity value
Finally, the value of the productivity potential is calculated based on
either turnover or total labour costs.
For a company or organisation operating on a profit-making basis, the
annual productivity potential (in euros) is arrived at by multiplying the
total productivity potential (%) by turnover (in euros).
For a non-profit company or organisation, the annual productivity
potential (in euros) is arrived at by multiplying the total productivity
potential (%) by the total annual expenses (total labour costs (in euros)).
The expected investment can be divided by the annual productivity
potential (in euros) in order to determine the payback time. The return on
investment (ROI) in % can be calculated by dividing the annual productivity
potential by the expected investment and multiplying it by 100%.
801. Oseland, N., & Burton, A. (2012). Quantifying the impact
of environmental conditions on worker performance
for inputting to a business case to justify enhanced
workplace design features. Journal of Building Survey,
Appraisal & Valuation, 1(2), 151-165.
133

134

9
TRANSLATING THEORY INTO PRACTICE
135

COST OF A WORKSTATION IN AN OFFICE ENVIRONMENT
Calculations show that a typical workstation in a Dutch office environment measures 20 m2. The
average cost of an individual workstation, based on 2019 price levels, amounts to € 490/ m2 per
year. This total amount includes building costs, as well as costs of facility services and the ICT
infrastructure. According to the Netherlands Facility Costs Index the cost of a workstation totals
9K €/year. So, this indication seems reasonably well in line with the calculations we analysed.
In the Netherlands a typical office building measures 625 m2 and it usually has 25 to 35 employees.
Table 9.1: Energy costs.
Overview of cost of energy consumption in offices (2020 rates)
Annual energy consumption per m2
m3 of gas
Electricity* kWh
less than 20 persons 18 60
more than 20 persons 20 115
costs per unit in € ** and *** excl. VAT 0.66 0.18
Average costs per year m2
in € in €
Less than 20 persons 11.88 10.80
more than 20 persons 13.20 20.70
Average costs per year per workstation
in € in €
Less than 20 persons 237.60 216.00
more than 20 persons 264.00 414.00
*) Including ICT, lifts, lighting and cooling.
**) Based on the average of the largest 5 suppliers in 2020; gas price is € 0.80 including 21% VAT.
***) www.pricewise.nl year end 2020 including 21% VAT charged over the net rate is 0.22/m2
A few remarks about the overview above:
- Research has demonstrated that energy costs
tend to rise disproportionately when more than
20 people work in a building.
- The average energy costs per workstation per
year amount to € 315 for electricity and € 250
for heating excluding VAT (2020 price levels).
Labour costs
Based on 2018 data from the Dutch statistical office,
the labour costs per employee - averaged out for all
employment sectors in the Netherlands - are € 35/hour.
The mean varies greatly between sectors, ranging from
€ 20/hour to € 56/hour.
136

Average costs are highest in the financial services
industry, while the lowest are found in commercial
trade (€ 28/hour) with intermediate levels for public
administration (€ 45/hour) and corporate services,
excluding employment agencies (€ 38/hour).
In the Netherlands we mainly use gas to heat spaces,
the cost of which amounts to approximately € 250
per year per workspace excluding VAT. The cost of
electricity is fractionally higher and a substantial part
of it goes to lighting .
The calculation is based on an average of 1,500 effectively
worked hours per year. This 1,500 hour figure is the net
result of decreasing the gross number of hours per year
(2,080 = 52 x 40 hours) with 25 holiday entitlements, 56
hours for public holidays, 3% for absenteeism and 2% for
training purposes and by applying a further deduction of
200 hours for other reasons. Employer contributions to
social security and retirement plans are included in this
figure. Given an average hourly rate for office work, the
total per year per employee is € 63.000.
By way of comparison: based on statistical data from 2017
with an average of € 36/hour in the Netherlands, the average
hourly rate in the EU is € 28/hour, with the highest rate in
Denmark (€ 43/hour) and the lowest rate in Italy (€ 29/hour).
Impact of the cost of dynamic
solar and daylight shading.
Implementing dynamic solar and daylight shading in
a building has a number of consequences. For one
thing, building expenses will increase. In a scenario with
dynamic solar and daylight shading devices, allowing
10% for the purchase price of servicing and repairs,
the total cost based on a 10-year economic life will be
approximately € 175 per workstation per year. In theory,
compared to a scenario without any shading facilities in
a standard building, this would mean that extra costs are
incurred for a workstation.
For our cost estimate our starting point was the implemen
tation of both dynamic solar and daylight shading.
Summarizing, the following observations can be made:
- The total fixed cost of a workstation in an office
environment consists of accommodation costs
and energy and labour expenses, amounting to
approx. € 73.000 per year in total, based on price
levels in 2020.
- The global breakdown per year would be:
• Housing € 9,500
• Energy € 565
• Wages and salaries € 63,000
- Energy costs represent less than 1% of a
workstation's total cost.
137

Energy savings that can be attributed to the use of
dynamic solar and daylight shading largely depend on
the solar orientation of the façade, the proportion of glass
surfaces in the façade, and the type of dynamic solar and
daylight shading applied. Using one of the current models,
indicative savings on electricity costs for cooling were
found to amount to € 8/ m2 per year for the Dutch context.
Depending on the average glass surface per workstation,
the total expected cost savings per workstation in the
Netherlands range anywhere between € 10 to € 80 per
year per unit. If we base the calculation on glass being
20% for the average workstation, the savings will be €
32 per year. Of all the scenarios, dynamic solar shading
contributes most to these savings.
The question remains in what way does applying dynamic
solar and daylight shading impact on productivity? The
very question we are trying to answer in this book.
We decided to answer this question from the perspective
of office worker productivity. In what way is their
productivity affected by adopting a dynamic solar and
daylight shading scenario?
From an economic point of view, productivity is the
relation between efficiency and effectivity that an
organisation can harness to convert means of production
(sacrifices) into results.
An essential step in developing the theory is the
connection between daylight during working hours and
productivity. In our research we have been able to benefit
from a large number of scientific publications that give
insight into the connection between both variables. There
is a positive link between both, but at the same time
various publications have also demonstrated that “too
much” can be counterproductive.
Too much daylight can indeed lead to a reduction
in thermal and visual comfort, which is definitively
detrimental to productivity. In that case it is necessary
to reduce exposure to light and a way to do this is by
implementing dynamic solar and daylight shading.
Productivity gains from the use of
dynamic solar and daylight shading.
In general, the productivity of an organisation can be
measured by focusing on the output of a process, for
example turnover, or costs, in economic terms: the
sacrificed means of production. In the context of office
work the 'sacrifices’ would refer to employees’ wages
and salary costs.
It is obvious that both approaches will produce a different
outcome if a for-profit organisation is concerned. In
the case of non-profit organisations, we can only base
this on the labour costs. On the other hand, if we are
referring to a profit-driven organisation without an office
workforce, the basis for the calculation is lacking.
Buildings without any daylight at all do not provide
a basis for calculation either. Those offices are,
incidentally, not allowed in the Netherlands. According
to the Building Decree 2012, in line with NEN 2057,
a minimum amount of m2 glass surfaces was made
mandatory for offices. The minimum requirement for
an office environment was set at 2.5% of the staying
surface. For a 20 m2 workspace that would imply having
a window of 0.5 m2, which would be highly unlikely in a
real-world office.
138

139

The proportion of glass per interior surface is much
higher than that and indeed is still on the increase in
contemporary architecture.
In this book we have developed a theory-based model that
provides a perspective on the potential productivity gains
based on different variables relating to a building and its
occupants. The result of the calculation is determined by
10 to 20 situation-specific variables. Erring on the side
of caution, it is realistic to work with productivity gains
varying from 1 to 3% on an annual basis, bearing in mind
the times certain weather conditions can occur in a year.
Special weather models exist for this purpose, and we
used them for the calculation.
Calculating productivity gains in
non-profit organisations.
With reference to the previous explanations about
the average labour costs in the Netherlands, the total
expected savings, allowing for a tentative 1 to 3%, are
€ 630 to € 1,890 per year, depending on the situation.
Calculation of productivity gains in
for-profit organisations
For organisations operating on a profit-making basis,
we use the average turnover per employee as a basis,
which can be very different for each sector, ranging from
€ 200,000 to € 600,000 per employee per year, and for
individual companies even far beyond that amount.
Conclusions
Allowing for an economic life of 10 to 15 years, the cost of
solar and daylight shading amounts to approx. € 175 per
workstation per year.
Both the energy savings for cooling during summer and
improved workforce productivity contribute to the ROI
offered by dynamic solar and daylight shading. Those
same elements will also determine the payback time of
the investment.
Table 9.2: Amounts per workstation per year.
Low
High
Energy cost savings (cooling) 10 80
Productivity gains
- Non-profit organisations 630 1,890
- For-profit companies 2,000 18,000
Non-residential buildings
Reaching 1.7 billion euros during the third quarter of
2020, the total construction costs in non-residential
buildings for which a building permit has been granted
in the Netherlands surpassed that of the preceding year
by nearly 24%. This increase can be largely attributed
to the increased construction costs of new commercial
property development. It showed a growth figure of more
than 34% while the rebuild of utility buildings increased
by over 3%.
If we apply these percentages to the average turnover
we end up with a range of productivity gains varying
from € 2,000 (1% of200,000 per year) to € 18,000 (3% of
600,000 per year) per employee/workstation per year.
In October 2020 the working stock in non-residential
construction increased by 0.2 month compared to
September, moving up to a total of 9.6 months (source
Dutch Economic Construction Institute).
140

Table 9.3: Non-residential construction - key figures
2018 2019 2019 Q2 2019 Q3 2019 Q4 2020 Q1 2020 Q2
Building stock1 number, K 1,137 1,148 1,142 1,144 1,148 1,150 1,153
Completed number, K 9.5 10.4 2.5 2.3 3.2 2.6 2.5
Demolition number, K 3.7 4.5 1.1 0.8 1.2 1.1 0.9
Permits2 (new development) number, K 3.4 3.1 0.9 0.7 0.7 0.7 0.8
Investments billion euros 21.0 23.5 6.4 5.3 5.8 6.1 6.2
Building costs3 million euros 6,345 6,368 1,553 1,406 1,889 1,494 w1.723
New development million euros 4,373 4,303 1,088 937 1,248 941 1,238
Existing construction million euros 1,974 2,066 465 469 641 553 485
1 ultimo 2 permits can include multiple buildings 3 value of construction permits granted Source: www.bouwendnederland.nl
The value of building permits for new offices issued
between 2014 and 2019 is approximately € 550 million,
based on a four-quarter moving average. 2020 is not a
representative year due to the corona crisis.
Figure 9.1: Value of construction permits granted by building type.*
EUR mln
200
180
160
140
120
100
80
60
40
20
EUR mln
1000
900
800
700
600
500
400
300
200
100
Offices (I-axis)
Schools (I-axis)
Shops (I-axis)
Other non-residential buildings (r-axis)
Halls, warehouses, glasshouses
and stables (r-axis)
0
Q1 2013 Q1 2014 Q1 2015 Q1 2016 Q1 2017 Q1 2018 Q1 2019
0
* Based on four-quarter moving average.
Source: CBS, adapted by Rabobank, 2019
Construction costs in non-residential construction
vary greatly and correlate with, for example, the size
of the building, the design (luxurious or ordinary) and
the number of floors. The cost variation appears to
range from € 900/ m2 to € 2,000/ m2. For our global
approach we use an estimated weighted average of €
1,250/ m2 and assume that the majority of the offices
are of standard or ordinary design. Based on this and the
four-quarter moving average, our estimate is that 400 to
450 thousand m2 of new development can be achieved
annually, excluding offices that are built as part of other
construction types.
141

Figure 9.4: Building stock (reference date 1 January 2020).
Use of buildings Total stock Absolute vacancy Relative vacancy
number surface in m2 number surface in m2 number surface
Meetings 62 120 30 344 820 3 070 1 105 440 4.9% 3.6%
Health 22 820 17 421 900 820 168 730 3.6% 1.0%
Industry 198 970 216 450 070 14 330 7 979 910 7.2% 3.7%
Offices 96 260 60 314 980 9 100 3 774 960 9.5% 6.3%
Lodging 125 120 14 121 070 860 129 060 0.7% 0.9%
Non-residential with multiple functions 49 530 73 170 600 2 600 2 194 520 5.2% 3.0%
Education 13 870 31 593 260 370 494 440 2.7% 1.6%
Other 439 990 33 706 010 0.0% 0.0%
Sports 9 710 10 085 240 280 163 590 2.9% 1.6%
Shops 129 200 47 220 700 11 040 2 922 820 8.5% 6.2%
Total non-residential 1 147 590 534 428 650 42 470 18 933 470 3.7% 3.5%
Residential 7 891 790 952 783 560 179 570 19 961 450 2.3% 2.1%
Total properties 9 039 380 1 487 212 210 222 040 38 894 920 2.5% 2.6%
Summary:
Total accommodation excluding residential property 1 018 390 487 207 950 31 430 16 010 650 3.1% 3.3%
Shops 129 200 47 220 700 11 040 2 922 820 8.5% 6.2%
Residential 7 891 790 952 783 560 179 570 19 961 450 2.3% 2.1%
Total properties 9 039 380 1 487 212 210 222 040 38 894 920 2.5% 2.6%
Source: CBS/Statline, adapted by Somfy
On 1 January 2020 the Netherlands counted
over 9 million buildings with a total built area
of 1,5 billion m2 and a vacancy rate of 2.5%.
Of this total number, 7.9 million of the buildings
had a residential function, nearly 130,000
were shops and over 1 million represented
other use types. This category includes a total
of 96,260 office buildings. Of these 9.5% -in
terms of the number of real estate objects- was
vacant on the reference date. Measured as a
percentage of the built surface the vacancy
rate of offices was 6.3%.
142

Market potential
Existing buildings
Assuming a 25% glass surface per m2 of office space,
2 m2 on average per window and excluding vacant offices
from the calculation, we are left with approximately 7.1
million windows in existing offices.
If we assume an economic life of 10 years for solar and
daylight shading devices, at least 700,000 windows per
year will need new installations. If we could apply both
dynamic solar shading and daylight shading for all these
cases, we may conclude that active offices represent
a potential of € 420 million per year excluding VAT and
installation costs.
New development
Assuming 25% glass surfaces for spaces in the office
segment that are built annually, and based on the
average new development per year having 2 m2 per
window on average, the total would be over 50,000
windows per year representing a € 30 million market
potential excluding VAT and installation costs.
Total potential after correction
It may be a good idea to apply a correction factor to the
results that were found. Installing dynamic solar and
daylight shading on façades with a northern orientation,
for instance, will generally be less useful and there will
undoubtedly be more reasons for glass surfaces to be
excluded from the potential gains.
After a 40% correction to the total figure we come to a
market potential of no less than € 250 million, excluding
VAT and installations costs.
143

144

EDUCATION
145

146

10
EDUCATIONAL ARCHITECTURE
147

SOME BACKGROUND INFORMATION
Before addressing the question of how dynamic shading can contribute to the indoor climate
of schools, it may be useful to shed some light on the development of the architecture of
educational buildings.
When you look for information on this topic, one of the
first names that comes up nearly immediately is that
of Herman Hertzberger 1001 . He felt that schools should
provide a varied, stimulating environment with lots of
activities going on and room for flexibility. Rich countries
are becoming more and more knowledge-based and this
trend is driving change in the requirements for the design
of school buildings. Also, the equipment used by schools
today, is becoming increasingly expensive.
Psychologists and psychiatrists insist that surroundings
are of vital importance to children and their development,
as their first impressions are decisive for the rest of
their lives. Sadly, such considerations sometimes seem
underrated in programmes used by those founding,
funding, designing, building, and furnishing schools.
According to Hertzberger, over the past century there were
hardly any building types that had seen as little change
as school buildings. It wasn’t until the end of the 20th
century that different looking buildings started to appear,
although this was mostly limited to their exterior aspect.
This doesn’t take away the fact that throughout the years
quite a number of monumental schools were built.
Back in the 1920s and 1930s, local authorities were in
charge of schools. There were a few school buildings
that stood out, especially in Hilversum (Dudok) and
Amsterdam (Amsterdamse School). In those days it was
all about consistent use of materials and long hallways
lined with classrooms, which were nearly always situated
on the south-facing side. Today, classrooms that have a
specifically south-facing aspect seem to have become
less popular. An important change was that at a certain
point the central government was given more control
regarding the construction of schools, including the
orientation of classrooms. Before the war, architects
developed a taste for open air schools, which presumably
was an alibi to use lots of glass in their designs. These
‘glass’ schools were the opposite of the old solid brick
buildings and as such, offered a prospect of a new,
brighter world. Such buildings were not particularly
comfortable as far as the indoor climate was concerned,
but in time the use of other types of glass and solar
shades solved this problem. These buildings were also
the first to focus on issues like hygiene, health, space,
light, air, and view - aspects that are still essential today,
perhaps more than ever.
It wasn’t before the second half of the twentieth century
that the archetype school building (long hallways offering
access to classrooms) was radically changed due to new
educational insights. Slowly but surely conventional classroom
teaching started to give way to other types of education,
partly influenced by the Montessori teaching methods.
Secondary education classrooms were transformed from
group spaces into spaces dedicated to specific school
subjects, with students moving through the school
building to go to their classes.
148

Amsterdams Lyceum (Amsterdamse School)
149

In today's educational landscape, the emergence of
individual education and collaborative schoolwork has
resulted in a shift away from the traditional classroom.
In a sense, this trend coincided with cuts in education,
which in turn have led to pressure on the available
space in schools. Going from there, it was not such a big
leap to transform hallways into students’ workspaces.
Especially primary schools were given an extra challenge
to deal with: the influx of immigrants and the associated
language problems that often need to be addressed
in a one-to-one setting. In short: there is a growing
need for a mix of individual workspaces and spaces for
conventional, classic forms of education.
In the Netherlands, the construction of new schools is
funded by government. This explains why the building
programme and space are subject to strict regulations,
i.e. there is a strong focus on a classroom’s size, as well
as on the dimensions of the thoroughfares (hallways)
of schools. Surely, each and every square meter adds
to the building costs. On the other hand, the learning
landscape is prone to changing attitudes that determine
which learning means and buildings are required.
For example, the introduction of laptops, tablets,
mobile phones and television screens has changed the
requirements regarding indoor design and equipment of
school buildings. But it is more than that, the different
backgrounds and varying intellectual levels of students
are having a large impact as well. Not to mention groups
of students lacking motivation and focus, or students
with complex home situations. Education and building
design are subject to all these aspects and more. The
latest trend is deschooling or homeschooling, which has
emerged under the Covid pandemic.
In the following years hundreds of schools in the
Netherlands will need to be renovated 1002 for a number
of reasons. A brief overview:
1. In sustainable societies there is a natural
shift away from new development in favour
of renovation. Existing spaces are retrofitted,
creating more room for quality. Critical studies
have pointed out that school buildings 1002 are
becoming disorganised due to all kinds of
regulations that change every so many years,
creating a lack in the consistency of the work to
be done in school buildings.
2. Improvement of the indoor climate and
undertaking renovations that have become
necessary.
3. New programmes of requirements;
existing buildings were founded on ideas
that have become outdated; educational
professionalisation.
4. Figures from previous experiences show
that reuse may be less expensive than new
development 1003 . Also, budgets made available for
the development of new schools are often 30%
below realistic building costs.
In 2013 the Dutch EIB (Economic institute for construction
and housing) published a scenario of forecasts where a
decrease of the number of students was envisioned with
an expected low point in 2022. Based on those numbers,
there would be no or less need for expansion. Schools
may experience a decrease in student numbers locally or
regionally for other reasons too.
150

As of January 2015, school boards have gained more power
over decisions involving maintenance and adaptation of
buildings 1004 . At the same time, municipalities have been
given more freedom to evaluate care and wellbeing at a
local level. This has created opportunities for the qualitative
improvement of buildings (indoor environment, health), to
incorporate sustainability as well as align with changes
that are beneficial from a didactic point of view.
From 1 January 2015 onwards, school boards have
become responsible for the complete maintenance of
schools, both indoor and outdoor, including modifications
of buildings. This used to be a responsibility shared with
the municipality, but the general idea behind this change
is that school boards have better judgement in specific
situations. The same shift was seen in 2005 in secondary
education. The total budget for staff and material leaves
little room to rearrange budget items. For investments
in new developments and expansion, school boards are
financially dependent on the local authorities, who have
a duty of care for this purpose.
One of the decisive factors to either renovate or build
a completely new school is the expected life span of a
school building after the intervention. The current law
does not provide adequate guidelines for this, which
complicates matters. The revised 2012 Building Decree
does regulate, however, that different requirements are
set for refurbishment purposes than for new construction
(for which generally more stringent requirements apply).
Requirements for the insulation of buildings have
become more demanding though.
151

152

11
AVOIDING OVERHEATING IN CLASSROOMS
153

INTRODUCTION
In cooperation with bba binnenmilieu, Somfy developed the model “Avoiding overheating in
classrooms”. Its purpose is to give stakeholders involved in the realisation of the construction and
renovation of educational buildings a better understanding of the added value of implementing solar
shading and light shading systems.
In many schools overheating is a problem due to the
elevated external thermal load (solar radiation) and
indoor thermal load (high occupancy rate). Overheating
can be controlled by deploying high quality dynamic
shading combined with other passive measures, such as
night-purge ventilation in summer, or by means of active
cooling, e.g. central cooling equipment or individual
cooling units per classroom.
The selection tool shows the impact of both active and
passive measures. These findings are subsequently
translated into relevant results that tie in with the
Dutch programme of requirements Frisse scholen
(‘Fresh schools’) 1101 :
- The number of hours temperature limits are
being exceeded
- The cooling capacity required and an estimate
of the energy cost of cooling and night-purge
ventilation in summer.
The results can be applied to small-scale or large-scale
renovations and the development of new classrooms.
This overview helps decision-makers make sound
choices and it gives them insight into the possibilities
and performance of passive measures like dynamic
solar shading.
or in short, TO calculations for various scenarios involving
the classroom and the façade's construction (e.g.
different window sizes, dynamic shading or not). These
calculations were also used to better understand the
effect of the measures on the cooling capacity needed
to prevent temperature overshoots from exceeding
26°C. The results were then included in an Excel model
designed to simulate all the outcomes for all the
combinations deemed relevant.
The Somfy selection tool “Avoiding overheating in
classrooms” gives users an estimate for overheating and
the cooling capacity needed in a classroom in all kinds of
situations. Please note that the list of simulations is not
exhaustive as not all possible variants and combinations
were simulated.
Backgrounds
The model was developed to investigate the major
effects of various measures and design options on the
temperature in classrooms during the design stage
or development phases. For an exact estimate of the
number of overshoot hours and the effect of measures
to counter them, a TO calculation should be made
specifically for the building concerned.
The tool's principles are based on the Programme
of requirements Frisse scholen (‘Fresh schools’).
We've worked out temperature overshoot calculations,
Starting points
An adequate indoor climate in schools is of major
importance to the health of students and teachers,
154

as well as for the students’ learning performance.
Climate change increases the chance of classrooms
becoming too hot and these increased temperatures
could have a negative impact on the learning
performance of students 1102 . In order to avoid
overheating, the implementation of cooling strategies
is an obvious solution. What would certainly make even
more sense is to adapt, use and design schools in ways
that minimize the risk of overheating, and that offer
possibilities to control the temperature experienced, i.e.
passive measures. These could include dynamic solar
shading, summer night-purge ventilation and increased
air velocity by using windows that can be opened. Apart
from preventing overheating, the use of solar shading or
light shading solutions will also help avoid glare produced
by direct solar radiation in the classroom.
Annoying reflections, for instance on the smartboard,
television or computer screens can be prevented using
light shading or solar shading solutions. In accordance
with the ‘Fresh schools’ Programme it is imperative
to have a solution for glare. We decided to incorporate
outdoor solar shading in the model - rather than
an indoor solution - because of the possible risk of
vandalism in classrooms and the performance rate
of outdoor solutions in preventing overheating. Even
though the selection tool was developed for standard
classrooms in primary and secondary education, the
main results could be used for any educational or training
institution with classrooms occupied by approximately
30 students and a teacher.
155

156

12
MODEL AND SELECTION TOOL
157

MODEL COMPONENTS
The model was set up using four different components that need to be followed one step at a time by
answering a number of predefined questions.
1. Establish characteristics of a classroom
(reference)
The key characteristics of a classroom and their
parameters are established using a number of
parameters.
- First of all, the aspect of the façade, i.e. north/
east/south/west. Choose the orientation that most
agrees with the orientation of the windows in the
building's façade.
- The next item involves the type of glass used, with
just two options: Yes/No. For reflective glazing a
g-value (factor for sun entering a space) of 0.4 is
used - for non-reflective glazing the value is 0.6.
- The following item is a global assessment of the
building mass. There are three options: Light, Midheavy
or Heavy.
• Light: the interior of the façade has been
insulated and coated with a surface coating, the
concrete floor and ceiling are also coated and
the inner walls are both insulated and coated.
• Mid-heavy: the interior of the façade is made of
brickwork, the floor/ceiling is concrete with a
coating, the walls of the hallways are made of
brickwork, the dividing walls are both insulated
and coated.
• Heavy: the interior of the façade is made of
brickwork, the concrete floor and ceiling are
coated and the inner walls are made of concrete
or brickwork.
- The next question focuses on the global
percentage of glass used in the façade, with a
number of options
• Low < 30%
• Average 30-60%
• High > 60%.
The option “Low” corresponds with a glass percentage of
25%, “Average” with 50% and “High” corresponds with a
percentage of 65%.
Together these answers result in a reference model
that serves as the starting point for calculations of the
impact of passive measures. To find out what the impact
of dynamic solar shading and other passive measures
is, it is imperial that the reference does not include solar
shading or any other measures against overheating.
158

2. Estimate of number of hours exceeding temperature limits
For the reference classroom an estimate was made of the number of hours the
temperature in the classroom exceeded the temperature limit set in the ‘Fresh schools’
Programme for Class A, B and C. The values are provided below in hours per year and
hours per month.
Estimate of the number of hours the ‘Fresh schools’ temperature limits are exceeded
per year (left) and per month (right).
1400
250
Number of usage hours per year
the temperature limit is exceeded
1200
1000
800
600
400
200
Number of usage hours per month
the temperature limit is exceeded
200
150
100
50
0
Overshoot
Overshoot
0
Overshoot Jan Feb March Apr May June July Aug Sep Oct Nov Dec
Number of usage hours per year
the temperature limit is exceeded
The impact 600 of the implementation of dynamic 100 solar shading in the reference classroom
can be seen below for the same limits. The
50
dynamic solar shading variant is compared
0
0
to the variant Overshoot without Overshoot solar shading. In the figure below, the number of usage hours is
displayed on the left, while on the right-hand side the difference between both situations
ANumber of usage hours per year
the temperature limit is exceeded
1400
1200
1000
800
400
200
1400
1200
1000
is visualised. The selection tool also shows the results per month.
800
600
400
Comparison of the situation without and with dynamic solar shading.
200
Number of usage hours per month
the temperature limit is exceeded
250 Overshoot Class A Overshoot Class B Overshoot Class C
200
150
Overshoot Jan Feb March Apr May June July Aug Sep Oct Nov Dec
Overshoot Class A Overshoot Class B Overshoot Class C
ANumber of usage hours per year
the temperature limit is exceeded
0
1400
Overshoot
Class A
1200 Reference (no solar shading)
1000
800
600
400
200
0
Overshoot
Class A
Reference (no solar shading)
Overshoot
Class B
Overshoot
Class B
Overshoot
Class C
With solar shading
Overshoot
Class C
With solar shading
-300 -250 -200 -150 -100 -50 0
Difference in the number of overshoot hours of the limit value by using solar shading (hours per year)
Class C Class B Class A
-300 -250 -200 -150 -100 -50 0
Difference in the number of overshoot hours of the limit value by using solar shading (hours per year)
Class C Class B Class A
The right side of the figure shows the difference between both situations so that it
becomes clear what the “gain” of the use of solar shading solutions would be.
159

3. Additional measures to avoid overheating
Having compared the situation without (reference) and with dynamic solar shading,
the user can choose to take extra measures to avoid overheating by means of passive
measures and active cooling.
Passive measures
If the user opts for extra passive measures, the following items can be selected or
deselected as appropriate:
- Outdoor solar shading. Possible answers: Yes / No. Default value = Yes
- Natural ventilation (opening windows). Possible answers: Not/ 30%/ 100%. 100%
corresponds with the class B requirement for natural ventilation from the ‘Fresh
schools’ Programme of requirements.
- Night-purge ventilation in summer. Possible answers: Yes / No. For night flushing
in summer, the model assumes that the ventilation system (depending on the
indoor or outdoor temperature) is turned on or off, and that the capacity equals the
usage during the day (8.5 l/s per person).
The effect of these measures on the number of hours the temperature limits are
expected to be exceeded, is presented in the diagram (left section) while the right section
indicates how much cooling energy will be needed to keep the temperature below 26°C.
Number of hours of exceeding limits and cooling energy needed
1400
3000
ANumber of usage hours per year
the temperature limit is exceeded
1200
1000
800
600
400
200
0
Overshoot
Class A
Overshoot
Class B
Reference (no solar shading)
With solar shading
Passive measures – own choice
Overshoot
Class C
Annual cooling capacity needed to keep
the temperature <26°C (kW/h)
2500
200
1500
1000
500
0
Baseline With solar shading Passive measures of own choice
3000
2500
2000
Energy (kWh)
1500
1000
160
500
0
Cooling energy required Energy consumption -1200 -1000 -800 -600 -400 -200 0

Active cooling
If active cooling is the preferred choice, the user can enter the efficiency of the cooling
equipment 1200 or the cooling production (Coefficient of Performance (COP)). Based on these
ANumber of usage hours per year
the temperature limit is exceeded
1400
1000
200
data it is possible to calculate how much cooling capacity and energy are needed to keep
800
600
the temperature in a room below 26°C, either with or without dynamic solar shading. The
400
results 200
500
are provided in the following figure, which also illustrates the difference between
0
Overshoot
Overshoot
Overshoot
both situations in order to indicate the gain of dynamic solar shading in addition to cooling.
Class A
Class B
Reference (no solar shading)
With solar shading
Passive measures – own choice
Class C
Comparing energy consumption for cooling in a situation without (reference)
and with dynamic outdoor shading.
Annual cooling capacity needed to keep
the temperature <26°C (kW/h)
3000
2500
1500
1000
0
Baseline With solar shading Passive measures of own choice
3000
2500
2000
Energy (kWh)
1500
1000
500
0
Cooling energy required
per year
Baseline
With solar shading
Energy consumption
per year
-1200 -1000 -800 -600 -400 -200 0
Energy consumption (kWh)
Energy consumption per year
Cooling energy required per year
Absolute values (left), differences relative to the reference situation (right).
161

4. Overview of the results
The tool generates a summary listing the outcomes and gains of implementing passive
measures. The energy consumption is calculated using a COP of 3 (unless stated
otherwise). Based on this information, the associated CO2 emissions produced 1103
(environmental load) and cost of energy 1104 are also rendered.
Example: outcome of selection tool when choosing passive measures
to avoid overheating
Temperature overshoot hours
Baseline
Dynamic
shading
Decrease/
increase relative
to baseline
All selected
measures
combined
Decrease/
increase relative
to baseline
Class A 1240 1142 -98 605 -635 Hours
Class B 1133 943 -190 394 -739 Hours
Class C 989 745 -244 230 -759 Hours
Energy for night-purge ventilation in summer
You have opted for night-purge ventilation in summer.
This has a positive impact on the room temperature, but activating it will also cost energy:
Energy night ventilation in summer 0 0 0 314 314 kWh
CO₂ emissions 0 0 0 107 107 kg CO2
Electricity costs € 0 € 0 0 € 60 € 60
Per
year
Do you wish to use cooling as an additional measure? In that case it will pay to maintain the passive measures:
Baseline
Dynamic
shading
Decrease/
increase relative
to baseline
All selected
measures
combined
Decrease/
increase relative
to baseline
Cooling capacity required 2485 1531 -954 693 -1792 kWh
Energy consumption for cooling
(COP=3)
828 510 -318 231 -597 kWh
Energy night ventilation in summer 0 0 0 314 314 kWh
Total energy consumption 828 510 -318 545 -283 kWh
CO2 emissions 282 174 -108 79 -203 kg CO2
Electricity costs € 157 € 97 -€ 60 € 104 -€ 54
Per
year
Example: outcome of selection tool when choosing active measures
to avoid overheating
Baseline
Dynamic
shading
Decrease/
increase relative
to baseline
Cooling capacity required 2485 1531 -954 kWh
Energy consumption 828 510 -318 kWh
CO2 emissions 282 174 -108 kg CO2
Electricity costs € 157 € 97 -€ 60
Per year
162

163

164

13
REFERENCE MODEL: BASIC PRINCIPLES
AND BUILDING CHARACTERISTICS
165

REFERENCE MODEL
For a better understanding of the temperatures produced in a classroom in a year, we designed a
model for a ‘standard classroom’. This model is based on predefined assumptions regarding the
dimensions, occupancy of the room (e.g. number of students and lesson times), as well as the
technical construction and installation features of the classroom.
In the model, we assumed that the room had no
active cooling or passive measures in place to avoid
overheating. The starting points are described in
Appendix 1 and are based as closely as possible on
the performance requirements set out in the Dutch
Programme of requirements for fresh schools 2021
(see temperature requirements for the summer season
and requirements for natural window ventilation in
Appendix 4 in this section). The basic model consists of
four variants where the windows of the classroom are
north, east, south or west-facing.
Temperature limits in summer
For this basic model a year-round Temperature
Overshoot calculation (TO calculation) was created by
means of “DYWAG” software1301. The results were then
compared with the temperature limits mentioned in the
‘Fresh schools’ Programme 2021.
Temperature limits are dependent on the outdoor
temperature. This means that the indoor temperature
is allowed to be higher as the outdoor temperature
increases. See Appendix 3 in this section. Based
on this, we worked out by how many usage hours
(annually and monthly) the limits mentioned in the
Programme of requirements for fresh schools 2021 will
be exceeded if no interventions are implemented to
avoid overheating.
By way of example, in the graph the temperatures
calculated for an east-facing classroom are plotted
against the outdoor temperature. The green, yellow
and red lines indicate the limit value for the indoor
temperature for class A, B and C respectively. The
graph clearly shows that at an average outdoor
temperature of 14°C and higher, the indoor temperature
allowed will rise too.
Overview of the maximum temperature limits in a classroom.
Class C Class B Class A
Summer temperature
For the temperature in summer and the
transitional season a sliding temperature
scale is used, where the limits of the indoor
temperature limits increase slightly with
the outdoor temperature according to
the following formula: indoor operative
temperature = 0.33 * rolling average
outdoor temperature +16.4 ± 4ºC.
For the temperature in summer and the
transitional season a sliding temperature
scale is used, where the limits of the indoor
temperature limits increase slightly with
the outdoor temperature according to
the following formula: indoor operative
temperature = 0.33 * rolling average
outdoor temperature +16.4 ± 3ºC.
For the temperature in summer and the
transitional season a sliding temperature
scale is used, where the limits of the indoor
temperature limits increase slightly with
the outdoor temperature according to
the following formula: indoor operative
temperature = 0.33 * rolling average
outdoor temperature +16.4 ± 2ºC.
166

Calculated indoor temperatures dependent on average outdoor temperature.
The graph shows that without additional measures the
calculated indoor temperatures will fairly soon exceed
the limits of the indicated area. Appropriate measures
will be necessary.
Energy consumption, CO2 emissions and costs
For all variants an estimate was made of the cooling
capacity needed to keep the room temperature below
26°C. The amount of energy needed to realise this
exact cooling capacity was calculated assuming a COP
(Coefficient of Performance) value of 3 for the cooling
equipment.
The energy needed for night-purge ventilation in
summer was determined by estimating the capacity
of the ventilation system and the number of hours
it is switched on during the night. The capacity was
estimated using the following formula:
Capacity [kWh] = 1.6 * flow rate [m3 /hour] *
pressure [kPa] * (flow rate at night / flow rate of design)
The following was assumed:
- Air supply pressure is 1.25 kPa
- Capacity determined per hour based on the
TO calculation
- Capacity of modern ventilation equipment
(direct current) is ± 25% less.
Next, the associated CO2 emissions were calculated.
We assumed CO2 emissions of 0.34 kg/kWh
(source: NTA8800).
The cost of energy consumption was calculated based
on a price of €0,19 per kWh.
167

168

14
TEMPERATURE OVERSHOOT
AND COOLING LOAD CALCULATIONS
169

REFERENCE FOR VARIANTS BASED ON
BUILDING CHARACTERISTICS
In order to analyse the impact of a number of key building characteristics on overheating in the
classroom, we have created a few variants of the base model. This way, the model will reflect the
existing situation or design more closely and it allows us to examine different cases. For example,
assumptions can be made as to the amount of glass in the façade (little, average or a lot of glazing),
the building mass (light, medium or heavy), whether or not the building has reflective glazing and the
façade’s orientation. The basic principles are described in Appendix 1 in this section.
Based on a selection of these parameters, a reference
model is drawn up for a project (see Table 5 for the 18
possible variants). We worked out the TO for the variants
marked with an “x” in the table below. Based on those
results we estimated the TO for the remaining variants,
indicated by “-“ 1401 .
For all variants, the calculations were carried out
for windows facing north, east, south and west. The
base model’s different variants are used as baseline
(reference) for the calculation of the impact of
passive measures.
Passive measures
The classroom reference model (one of the 18 options
from the table above) is the tool's baseline state which
we need to understand the effect of passive measures
on overheating in classrooms.
The effect on the number of overshoot hours per month
is shown for the following measures:
- Availability of outdoor solar shading;
Possible answers: Yes / No
- Natural ventilation (by opening windows);
Possible answers: No/ 30%/ 100%
- Possibility for night-purge ventilation in summer;
Possible answers: Yes/ No
These measures, which can be found in the following
table, allow up to 12 possible combinations of passive
measures. The principles behind each measure are
described in Appendix 2 in this section.
Overview of all the different variants at baseline (classroom).
Reflective glazing Building mass Low glass % Average glass % High glass %
Light - x -
No
Mid-heavy x x x
Heavy - x -
Light - x -
Yes
Mid-heavy x x x
Heavy - x -
170

171

Overview of possible combinations of passive measures.
Outdoor solar shading Natural ventilation No summer night ventilation Summer night ventilation
None Reference/baseline X Y
No
Little (30%) X -
Considerable (100%) X Y -
None X Y X
Yes
Little (30%) - X
Considerable (100%) - X
Again, this is not an exhaustive list of all possible
combinations (12 variants of passive measures x
4 orientations x 18 reference model variants = 864
possibilities). The relative effect of the passive measures
for the combinations in the table above displayed with an
“X”, were calculated for the baseline without any dynamic
reflective glazing, mid-heavy building mass and average
glass percentage. Subsequently, the combinations
indicated with a “Y” were also calculated for the reflective
glazing variant (reflective glazing, mid-heavy building
mass and average glass percentage), light building
mass (no reflective glazing, light building mass and
average glass percentage) and heavy building mass
(no reflective glazing, heavy building mass and average
glass percentage).
Based on these findings, for every combination of
passive measures and reference models an estimate
was made of the effect passive measures have on the
number of temperature overshoot hours. The effect was
determined separately for each façade orientation. The
results of these calculations were integrated into the model.
Night-purge ventilation in summer utilizes the lower
outdoor temperatures in the evening and at night to cool
the building down. Consequently, at the start of the new
school day the indoor temperatures will be lower and
there will be less temperature overshoots and/or less
energy demand for cooling.
Dynamic outdoor shading prevents direct solar radiation
from coming in, leading to lower thermal loads and
consequently less overshoot hours of the temperature
allowed or desired. Or, where cooling equipment is used,
less energy to cool the building.
By opening windows, indoor heat (produced by students,
teachers, lighting and ICT equipment) can be flushed
out if the outdoor temperature is lower than the indoor
temperature. Especially on sunny days in springtime
and autumn this can effectively contribute to preventing
overshoots of the desired indoor temperature and/or a
decreased cooling demand.
172

Cooling energy required
Finally, we worked out how much cooling energy would
be needed to prevent the indoor temperature from
exceeding the 26°C mark (temperature limit for active
cooling mentioned in the Programme of requirements
for fresh schools 2021- class B). Here no distinction
was made between the various ambition levels of
‘Fresh schools’, since both in new construction and for
significant renovations the advice would basically always
be to strive for class B performance. For temperature
overshoots, however, all these ambition levels are used
to show the performance in the area of thermal comfort.
To determine the amount of energy needed for cooling
purposes, the DYWAG software was used once again
for calculations. These were carried out for the variants
indicated with an “x” or “y” in the two tables above.
For each orientation the impact was worked out
individually. Based on these results, we estimated the
required cooling capacity for all variants. Next, this
outcome was used to calculate the energy consumption
(power needed to generate cooling energy) and to
estimate CO2 emissions. Energy consumption was
determined by dividing the required amount of cooling
energy by the assumed level of efficiency of the cooling
equipment.
The default value of COP, Coefficient of Performance,
in the tool is ‘3’ 1402 . This means that the cooling
equipment needs 1 kWh to generate 3 kWh of (cooling)
energy. The higher the COP value, the more efficient
the cooling machine. The associated CO2 emissions
are subsequently determined by multiplying the energy
consumption of the cooling equipment by the assumed
CO2 emissions for 1 kWh of power 1403 .
1001 Herman Hertzberger is a Dutch architect born
in Amsterdam (1932). He was internationally
acclaimed for his architectonic and theoretical
contributions to a movement in architecture called
Structuralism. In 2012 he was proclaimed best
Dutch architect by his colleagues and in the same
year he received the prestigious Royal Gold Medal
for his complete body of work.
1002 Broekhuizen, Dolf. Scholenbouw atlas, page 17.
1003 Broekhuizen, Dolf. Scholenbouw atlas, page 19.
1004 Wijzigingen van de Wet PO, WEC, en PO BES 2012-
2013
1101 https://www.rvo.nl/sites/default/files/2021/06/
PvE-FrisseScholen-2021.pdf 2
1102 Wargocki, P., Porras-Salazar, J. A., & Contreras-
Espinoza, S. (2019). The relationship between
classroom temperature and children’s
performance in school. Building and Environment,
157, 197-204.
1103 NTA8800 CO2 emissions coefficient for electric
facilities: 0.34 kg/ kWh.
1104 Based on a price of 0.19 eurocent per kWh.
1301 Dynamic simulation (DYWAG) - DGMR Software
version 2021.1
1401 Example: the monthly and annual overshoot hours
of a classroom of light building mass with little
glass were calculated by multiplying the relative
influence of little glass compared to average use
of glass (for mid-heavy building) with a situation of
average glass percentage and light building mass.
1402 NTA8800 COP electrically powered compression
refrigerating machine without further
specifications
1403 COP 3 10 NTA8800 CO2 emission coefficient for
electric facilities: 0.34 kg/ kWh
173

174

APPENDIXES
175

APPENDIX 1
Temperature overshoot calculation
General assumptions: Climatic year: NEN5060-1% (2018)
Assumptions for all scenarios:
- Fully occupied classroom, 30 12-year-old students and 1 teacher
- Activitity 1,2 MET
- Surface and height of room: 7*8 = 56 m²; height 2.8 m.
- Basic ventilation: Class B 8.5 l/s pp between 08:00 – 17:00
- Mechanical ventilation 'Fresh schools' Programme Class B
- Air infiltration: qv 10 0.4 dm3 /s per m² (qv10 is part of BENG).
• Existing building: 0,4 as a complete façade (Class C) and 0,4 Class B.
- Usage hours 08:00 – 17:00 of which
• 8:00-15:00 30 students and 1 teacher
• 15:00-17:00 1 person (teacher)
- Activity: metabolism 1.2 MET, CO2 production 19 l/s per person.
- All other walls are interior walls
- Insulation values
• Rc-value exterior walls: 5.0 m2 *K/W
• Rc-value roof: 6.3 m2 *K/W
• Windows (frame incl. glass) U-value: 1.5 W/m2 *K
- Heat classroom up in the morning up to 20°C at 8:00 am.
- Classroom on top floor (flat roof)
- Installation switched on between: 7:00-18:00
Usage:
- Internal heat load of one computer (teacher) and smartboard, students without laptops
- Periods including summer break and Christmas break.
- No school: only during weekends en holidays + between Christmas and New
Year's Day
Passive measures:
- Dynamic solar shading available: no
- No natural ventilation
- Night-purge ventilation in summer: no.
176

Aspects regarding construction:
- Window orientation (north/east/south/west).
- Reflective glazing (yes/no).
- Reflective glass, g-value: 0.4 – Non-reflective glass, g-value: 0.6
- Building mass (light/mid-heavy/ heavy). An indication of the mass of a building
(ISSO publication 32):
• Heavy: the interior of the façade is made of brickwork; the concrete floor and
ceiling are coated; and the inner walls are made of concrete or brickwork.
• Mid-heavy: the interior of the façade is made of brickwork; the concrete floor
and ceiling are coated; the walls of the hallways are brickwork; the dividing
walls are insulated and coated.
• Light: the interior of the façade has been insulated and coated with a surface
coating; the concrete floor and ceiling are also coated; and the inner walls are
both insulated and coated.
- Percentage of glass surface in the façade (little/average/high).
• Little (25% - 2 x 2 m * 1.4 m)
• Average (50% - 2 x 3 m * 1.9 m)
• High (65% - 1 x 7 m * 2.1 m) Internal heat load
- Persons: 85 W per person (30 children and one teacher)
- Lighting: 7.5 W/m2
- ICT devices (smartboard + pc for teacher): 450 W per classroom
177

APPENDIX 2
Passive measures
Dynamic solar shading:
- Solar shading available (yes/no).
- Dynamic solar shading properties:
• Outdoor solar shading Fc value 0.20
• Down at <150 W/m2
• Up at >150 W/m2
Natural ventilation:
- No windows that can be opened
- 30% PvE FS Class B, C = 1.8 l/s per person)
- 100% PvE FS Class B, C = 6 l/s per person).
- Use of windows:
• Open windows at indoor temperatures >24ºC
• Close windows at outdoor temperatures >26ºC
• Close windows at outdoor temperatures <12ºC
• Close windows at indoor temperatures <20ºC
• Close windows at windspeeds from 3.0 m/s
Night-purge ventilation in summer:
- Night-purge ventilation present (yes/no)
- Starting points for night-purge ventilation:
• Minimum outdoor temperature 12ºC
• Maximum outdoor temperature 20ºC
• Minimum indoor temperature 20ºC
• Maximum indoor temperature 50ºC
• Minimum outdoor/indoor difference 3ºC
• Maximum outdoor/indoor difference 50ºC
• Between 8:00 pm and 06:00 am summer night-purge ventilation is active.
• From Monday to Sunday
• Capacity is 8.5 l/s per person (based on 31 persons)
178

APPENDIX 3
Calculated room temperature
Graphic representations of the effect of façade orientation
Situation at baseline:
- No reflective glass
- Mid-heavy building mass
- Average glass percentage
- No passive measures or cooling applied
179

Graphic representations of the effect of façade orientation
Situation at baseline:
- No reflective glazing; mid-heavy building mass and average glass percentage
- Effect of passive measures on south-facing façade
No solar shading
Dynamic solar shading plus night ventilation
Dynamic solar shading
Dynamic solar shading plus overnight
ventilation plus open windows (100%)
180

APPENDIX 4
Programme of requirements Frisse scholen (‘Fresh schools’) 2021
– Summer temperature and natural ventilation
Temperature Class C - Sufficient Class B - Good extra compared to Class C Class A - Excelent extra compared to Class B
Summer
temperature
• For the temperature in summer and the
transitional season a sliding temperature
scale is used, where the limits of the indoor
temperature limits increase slightly with
the outdoor temperatuur according to the
following formula:
• For the temperature in summer and the
transitional season a sliding temperature
scale is used, where the limits of the indoor
temperature limits increase slightly with
the outdoor temperatuur according to the
following formula:
• For the temperature in summer and the
transitional season a sliding temperature
scale is used, where the limits of the indoor
temperature limits increase slightly with
the outdoor temperatuur according to the
following formula:
• indoor operative temperature = 0.33 rolling
average outdoor temperature +16.4 ± 4ºC.
Comment:
• The adaptive requirements (sliding temperature
scale) are based on (inter)national
standards and guidelines, such as NEN-EN
16798-1 (Annex B2.2) and ISSO publication
74, corrected for the situation in schools.
This requirement can only be applied in
buildings with windows that are easy to
open and if students are free to choose the
clothes they want.
• Requirements for the maximum operative
temperature in situations without passive
cooling are in accordance with NEN-EN-
ISO 7730. This additional requirement is
appropriate in situations where it is not
possible to open windows, with active cooling
that can be controlled locally or where
there is no freedom of choice of clothing
(uniforms).
• The upper limits for the operative temperature
in summer are appropriate for an
outdoor running mean temperature of 14ºC
to 22ºC. The lower limits apply at a running
mean outdoor temperature of 17ºC to 22ºC.
• Parameters are established as per the
regulations in NEN-EN-ISO 7726.
• For temperature overshoot calculations the
reference year RA2018T1 (in accordance
with NEN 5060) is followed.
• indoor operative temperature = 0.33 rolling
mean average +16.4 ± 3ºC.
• In situations without passive cooling
(e.g. spaces without windows that can be
opened or spaces with locally controllable
active cooling) an additional requirement is
that the operative temperature should not
exceed 26ºC.
Comment:
• indoor operative temperature = 0.33 rolling
mean average +16.4 ± 2ºC.
• In situations without passive cooling
(e.g. spaces without windows that can be
opened or spaces with locally controllable
active cooling) an additional requirement is
that the operative temperature should not
exceed 25.5ºC.
Comment:
Air Class C - Sufficient Class B – Good extra compared to Class C Class A - Excellent extra compared to Class B
Natural ventilation
• The capacity of natural ventilation facilities
is at least 6 dm /s per m floor area.
• The capacity of natural ventilation facilities
at space level is at least 6 dm /s per m of
floor area.
• The capacity of the natural ventilation
facilities at space level is at least 9 dm /s
per m floor area.
Comment:
• The natural ventilation capacity must be
determined as per NEN 1087 regulations.
Comment:
• In order to meet the Class B requirement
a 50 m classroom with elements that can
be opened on n side should be able to be
completely opened at least 3,0 m. If any
windows cannot be fully opened, more
windows are required in the room.
Comment:
• In order to meet the Class A requirement a
50 m classroom with windows that can be
opened on the n side, should have at least
4,5 m of elements that can be fully opened.
If any windows cannot be fully opened,
more windows are required in the room.
The complete PvE can be downloaded via the following link: https://www.rvo.nl/sites/default/ files/2021/06/PvE-Frisse-Scholen-2021.pdf
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182

HEALTHCARE
183

184

15
HISTORY AND ARCHITECTURE OF CARE BUILDINGS
185

CARE FOR THE ELDERLY 1501
The history of care and housing for the elderly can be traced back as far as the Middle Ages. In the
Netherlands, the period from the 13 th century onwards saw the construction of ‘hofjes’, clusters of
almshouses arranged around a courtyard and forming a type of small community for the elderly. The
17 th and 18 th centuries witnessed a significant increase in the construction of hofjes. Some of those
complexes still exist today and many of them (such as the Hofje van Nieuwkoop in The Hague, the
Pepergasthuis in Groningen and the Hofje van Bakenes in Haarlem, dating from 1395) have been
designated as urban conservation areas. Hofjes were often constructed in an urban setting around an
open space in the vicinity of a church. The start of the 20 th century then saw the development of the
retirement home, also known as a home for the elderly (Dutch: ‘huis voor ouden’) or a retirement home
(Dutch: ‘huis voor ouden van dagen’ or ‘rusthuis’). These consisted of apartments specifically designed
for elderly people, situated within a complex providing communal facilities.
In 1916, the ‘Alkmaar’ Public Housing Association
(Vereniging voor Volkshuisvesting ‘Alkmaar’) launched a
competition to design the Karenhuizen, a home for the
elderly in which the availability of fresh air and natural
light formed an important requirement.
In the immediate aftermath of the Second World War,
housing for the elderly left a lot to be desired; what
housing there was did not even fulfil the minimum
requirements. This was partly due to the housing shortage
was a result of significant wartime losses and partly due
to the fact that sufficient resources to provide housing of
an acceptable standard were simply unavailable.
New ideas also emerged. These were based upon an
elderly person’s reliance on care and distinguished
between various main types of housing, such as flats for
the elderly, retirement homes and care homes, serviced
flats and combinations of these. A major change took
place in the 1960s. Care for the elderly became fully
regulated by the government. This gave rise to a need for
the industrialisation, standardisation and upscaling
of elderly care, each of which was dictated by a need to
drive costs down.
The type of housing for the elderly that was constructed
most widely was the residential home (Dutch: ‘bejaardenoord’)
and was intended for elderly people requiring some
form of domestic care.
On a practical level, these were home to large numbers of
elderly people who would also have been capable of looking
after themselves. Large-scale developments closely
resembling blocks of flats were constructed that consisted
of several storeys and were equipped with centralised facilities
such as the kitchen. The living units themselves were
as compact as possible. In fact, they were so small that
they offered hardly any space for personal possessions.
In the early 1970s, the government concluded that the
population forecasts from Statistics Netherlands (CBS)
were too inaccurate for planning purposes. What is
more, it was realised that the country had set off along
a road that was turning out to be a dead end: caring
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187

for the elderly was becoming much too expensive. The
Exceptional Medical Expenses Act (AWBZ) then triggered
an increase in the construction of care homes for elderly
people no longer capable of living on their own. The care
homes themselves were set up in the form of hospitals
and were accompanied by the associated procedures
and guidelines. Between 1969 and 1976, this resulted in
the creation of around 25,000 additional beds in care
homes. The architecture of care homes focused on the
need to provide treatment and care and did not reflect
the need for such buildings to fulfil a residential role.
During the 1970s, people began to realise that perhaps
this was not the right way forward. At the same time,
interest in age-related psychiatric care was increasing.
The 1980s witnessed the emergence of a countermovement.
The size of developments was scaled back and
a more in-depth examination was carried out into the
difference between nursing and care. This formed a
precursor of developments in that decade, which brought
about a shift involving the separation of living and care.
A movement arose involving the construction of larger
buildings for the provision of care that were conceived
as mini-towns. As a matter of necessity, the economic
downturn in the 1980s gave rise to a form of large-scale
housing construction. A switch was made to a system
of subsidies for the construction of housing for elderly
people, in which the emphasis lay upon accommodating
elderly people in small, purpose-built homes.
A subsequent phase saw the advent of informal care,
based on the realisation that care had to become firmly
embedded within society. This provided scope for the
construction of an entire spectrum of buildings, in which
large buildings formed one extreme and care at home
formed the other. This change also led to an insight
that existing dwellings should be easily adaptable
further down the line. A further development was the
‘Seniorenlabel’ (Senior Citizens’ hallmark) – a nationally
accepted package of uniform requirements which, if
fulfilled, would certify that a dwelling is suitable for
occupation by the elderly. The fact that adapting existing
properties is not particularly efficient also led to the
development of dwellings that fulfilled the needs of
elderly people and were designed to offer adaptability
right from the outset. In practice, however, these
fulfilled only part of the needs that existed, namely the
two extremes at either end of the market: the need for
increased construction of social housing and the specific
needs of a small group of people of comfortable means.
For much of the 1980s, the way in which living and
caring for the elderly were reflected in architecture was
determined by programmatic aspects and aspects of
architectural theory. The separation of living and care
made it possible to move away from the customary
approach that involved defining specific types of
accommodation based on their function. This resulted in
a hybrid form, in which a single building was capable of
satisfying a variety of needs, according to the specific
physical situation of the residents. This took the form of
the ‘wozoco’ (a combined residential and care complex),
580 of which were completed between 1987 and 1998;
the foremost difference between these and more
traditional care homes was the size of the apartments
themselves. This signalled a move away from the
construction of residential accommodation and meant
that care now formed the sole pillar of policy-making.
188

As a result of the ageing population and the need to
replace outdated complexes, the construction of new
care homes has continued. What is more, the forms
of care on offer are becoming increasingly diverse. In
designing these homes, increasing interest is being
directed towards the world as experienced by elderly
people. After all, both the elderly people themselves and
the staff ought to be able to function in an environment
that makes them feel at ease.
The requirements that form a recurring feature in the
construction of new care homes are greenery, or at least a
view of a green landscape, natural light and good acoustical
properties. While some projects refer to the concept of
a ‘healing environment’, very few make any reference to
evidence-based design (the idea that manipulating the
environment can give rise to measurable effects).
What the future holds in terms of elderly care
Whatever concepts are devised in the future, old-age
will continue to form the final stage of life and for
that reason alone, a large proportion of elderly people
will require increasing amounts of care. In terms of
architecture, there are two extremes, namely the
importance attributed to the construction of residential
accommodation and, at the other end of the spectrum,
the development of (small-scale) living and care entities.
The existence, on the one hand, of adaptable dwellings
accompanied by a variety of tailor-made care provisions
that can be bought in and, on the other hand, of specific
types of living accommodation, including conventional
nursing and care homes, is in elderly people’s interest.
The conception that “I’m going to retire and the
government will take care of me from now on” is not
economically sustainable. Senior citizens of comfortable
means will need to bear the costs for themselves.
Healthcare 1503
The earliest dedicated care facilities existed as long ago
as antiquity and the Ancient Greeks were already making
use of complexes consisting of a variety of buildings.
During the course of the first few centuries after the birth
of Christ, the provision of healthcare was absorbed by
Christianity. The First Council of Nicaea, which was held
in 325 A.D., determined that every town must have a
place for the sick and the poor.
The xenodochia were the precursors of the ‘Hôtel-Dieu’
(hostel of God), responsibility for which was entrusted to
the bishops at the Council of Aix-la-Chapelle in 816.
The most well-known ‘Hôtel-Dieu’ was the one in Paris,
whilst the one that is of the greatest architectural interest
is the one located in the French town of Beaune (1443-
1451). Together with the monastic hospitals, such as the
one in Tonnerre (1293) and Angers (1153), these formed
the bedrock of charitable, religious healthcare in the
Middle Ages. In the majority of cases, the architecture
of these buildings imitates ecclesiastical architecture.
The emergence of cities in the thirteenth century, first in
Italy and Flanders and afterwards elsewhere, stimulated
the development of non-religious forms of healthcare.
In the eighteenth century, the church and cities received
support from the state as a champion of healthcare and
as a means of encouraging the building of hospitals.
Once the state had identified the fact that the people form
one of the most important foundations underpinning its
189

prosperity and (military) power, it initially set out to construct military
hospitals. These kept up with the latest scientific insights and, from a
technical perspective, were always far ahead of their time. In England,
the Royal Hospital Chelsea was set up in 1682 and the Royal Naval
Hospital in Greenwich was constructed in 1694, both of which were
designed by the architect and doctor Sir Christopher Wren. In contrast to
military hospitals, their civilian counterparts were intended as a means
of caring for the poor. This caused hospitals to become what they would
remain for many years to come: institutions that cared for the poor. In the
few decades that followed, dozens of hospitals were built, especially in
the German-speaking countries.
It was in those countries that the first corridor hospitals came into being.
The majority of those were relatively small institutions and though
they were specifically designed to serve the ailing poor, the structure
of the buildings themselves was essentially no different to that of
other prestigious buildings. The first corridor hospital, the Inselspital,
was designed by the architect F. Beer between 1718 and 1724 in Bern,
Switzerland. The wards were situated on opposite sides of a long corridor.
The introduction of open-ended rooms meant that the hospital, which
had a total of 45 beds, took on a completely different atmosphere. The
hospital in Bern was followed by the Charité in Berlin. The Charité, which
was established in 1727 in line with the Parisian model and contained
200 beds, was considerably larger than the hospital in Bern and was
more or less rectangular in shape. The corridor ran around an open
atrium and the wards, which were designed to accommodate 10 to 12
beds, were located on the outside.
The ‘Allgemeines Krankenhaus’ (General Hospital) in Switzerland was
one of the first hospitals to provide special facilities to ensure the supply
of fresh air and the removal of stale air that had probably become
contaminated as a result of coming into contact with the patients being
nursed there. The conviction that sickness was a result of harmful
vapours, known as miasma, dated back to the second century.
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191

Statistical analysis and medical cartography – two
important scientific innovations that arose in this period
– demonstrated the link that existed between the onset,
frequency and severity of illnesses and the physical
qualities of the various districts in the city. This also gave
rise to the logic that diseases could be combated by
making changes to the environments in which people lived.
Fresh air was regarded as the best remedy, which
explains why the first hospitals were designed to fulfil the
role of respiratory machines. This concept was developed
following the fire in the Hôtel-Dieu in Paris in 1772.
The abominable conditions in that hospital had long been
a cause of complaints.
Probably the most perfect example of a pavilion hospital
was constructed in Paris, where a new Hôtel-Dieu opened
its doors more than a century after the fatal fire of 1772.
It was designed by E. Gilbert, who – and this was no coincidence
– had previously made his name by constructing
a psychiatric clinic [Charenton, the final design of which
was dated 1838) and a prison [Mazas, constructed
between 1840 and 1850). The location of the new hospital
was decided upon by G.E. Haussmann – it was situated
on the north side of the square in front of Notre-Dame,
between the square itself and the main artery of the river
Seine.
Before the mid-19 th century, advances taking place in
other countries had little influence in Netherlands. The
corridor system was still in favour, a long time after it had
been rejected in France and Great Britain due to the fact
that it was outdated.
In the hands of capable designers, hospitals of that type
lent themselves to important innovations, but most of
those innovations were of a structural nature. A typical
example of this is the Coolsingel Hospital in Rotterdam
(1855), which was designed by W.N. Rose. The Coolsingel
Hospital was almost literally inspired by the Diakonissen
Anstalt Bethanian, which was designed by T.A. Stein
and constructed in Berlin between 1845 and 1847. For a
long time, the Coolsingel Hospital itself was also famous
outside of the Netherlands. The hospital’s fame was
due entirely to its technical facilities, which at the time
represented the state of the art. For example, it was fitted
with a sophisticated system of ventilation and had its
own water purification plant. The potential offered by the
steam engine, which was the most important invention
of the nineteenth century, was also utilised in full. But
despite the fact that the hospital was so far ahead of its
time in terms of its architecture and especially in terms
of its technical facilities, the corridor system on which its
design was based was already behind the times. A pavilion
system was used when the hospital was expanded later.
Just like the earlier corridor-based buildings, the pavilion
hospitals also consisted of wards for men and women and
wards for patients suffering from contagious diseases.
The importance of the pavilions was set to change within
a short time, however. In the late nineteenth century,
medical science was making rapid advances. The various
specialisms, such as gynaecology, obstetrics and
ophthal mology, were housed in different pavilions. On a
practical level, this approach was used in the construction
of university hospitals, such as the design by J. van
Nieukerken for the Algemeen Provinciaal, Stads- en
Academisch Ziekenhuis (the General Provincial, City and
192

University Hospital) in Groningen. In order to prevent
pavilion hospitals spreading out across extensive sites,
types of hospital were developed that formed a hybrid
of the corridor and pavilion types of hospital. In many
cases, the pavilions themselves were interconnected by
corridors, as in the Onze Lieve Vrouwe Gasthuis (Hospital
of Our Lady) in Amsterdam.
The ‘insane’ were often chained like animals and locked
up naked in dark cells, mostly because their deviant
behaviour made them a threat to public order in the city.
The asylum’s function as a place of confinement was
reflected in the structure of the institution itself, which
mostly consisted of a number of cells (initially only a
small number), grouped around a rectangular atrium. In
the centuries that followed, the number of institutions of
this type gradually increased.
The roots of the psychiatric hospital partly coincide with
those of the modern-day hospital: to identify psychiatric
conditions which, with the help of the very latest
scientific insights, ought to be treatable.
While new forms of nursing and newly adapted
institutions were being introduced in other countries, the
old ‘lunatic asylums', many of which had been set up
in the Middle Ages, were still in use in the Netherlands
(Reinier van Arkel in ‘s-Hertogenbosch, which dated back
to 1442 and the Willem Arntsz House in Utrecht which
dated from 1461). The founders of those institutions
were well-to-do citizens who, driven by their Christian
duty of charity, had left a bequest in their will. Until the
late eighteenth century, those establishments made no
attempt to cure the patients; they were simply kept there.
It was not until the 19 th century that institutions in the
Netherlands began to be constructed in rural locations.
The preferred model for the construction of those
institutions was the pavilion system. The major attraction
of such institutions lay in their ability to become fully
integrated within their rural surroundings, in the ability
for patients of different categories and classes to be
physically separated from each other and in a high
degree of transparency within each pavilion. One of the
benefits of the pavilion model was that an institution
could start out on a small scale and slowly expand over
time. Around the turn of the 20 th century, the size and
number of such institutions increased sharply.
In the second half of the nineteenth century, a new
category of mental illnesses was identified, which differed
from the category of the insane, due to the fact that
those particular mental patients mostly did not pose
any threat to society and were very much aware of their
specific problem. This group of patients had probably
existed the entire time, but they were now being classified
as belonging to a separate group. The fact that the
conditions they suffered from mostly occurred amongst
well-to-do sections of the population meant that they
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formed an exceptionally lucrative target group for the
many private clinics that sprang up in the final quarter of
the nineteenth century. Wentink concluded that clinics
treating neurasthenia ought to be established in an idyllic
location, only a short distance away from woods, gardens,
meadows and agricultural lands, due to the fact that the
landscape not only served as a place in which to go on
hikes and walks, but also provided opportunities to work
on the land. For example, having an operational dairy
farm on the site of a clinic was recommended, wherever
possible. A further recommendation was that the locations
selected should be situated in the vicinity of a city. This
not only facilitated the delivery of all types of practical
supplies, but it also made it easier to attend church
services and provided the patients with opportunities for
fun and entertainment as well. A clinic was supposed
to commence operations with two large pavilions, one
for first-class patients and the other for second-class
patients. A third pavilion for third-class patients would
be added subsequently. Stringent requirements were
imposed with regard to the architectural appearance of
such sanatoria. The rooms benefited from a large amount
of natural light and, where possible, included balconies.
Depending on its orientation, the southern, south-eastern
or south-western side of the building was to include a
large, spacious veranda.
Slowly but surely, the principles which, around the end
of the eighteenth century, had led to the advent of the
modern hospital and the modern psychiatric clinic started
to lose ground. Clean air and rural surroundings were still
regarded as important, but the belief in the contagious
nature of miasma disappeared when it was discovered
that it was not the polluted air itself, but the bacteria
contained within it, that were contagious. In addition, it
was found that only a small portion of those bacteria are
actually spread via the air. The discovery of bacteria meant
that designing hospitals in the form of large respiratory
machines was no longer necessary. The front line of
medical thinking shifted to the laboratories, which were
searching for ways of rendering bacteria harmless.
In the very same period, medical technology started to
play a dominant role inside hospitals. The first device
to make a widespread entry was the X-ray machine
and this was shortly followed by additional miracles of
technology. The triumph of medical technology changed
our hospitals from being a place that provided care to
the poor into an institution that provides cutting-edge
medical care. This, however, caused it to move beyond
the reach of its traditional clientele – the poor. As far as
the architecture of hospitals was concerned, the focus
once again lay upon identifying more compact forms
and the new status of a building frequently manifested
itself in the form of a markedly prestigious appearance.
Progresses in medical care were also being made in
the field of psychiatric medicine, however this did not
lead to a departure from the extensive complexes of
pavilions, but instead gave rise to greater differentiation,
partly due to the introduction of new treatments. Active
therapy in particular led to the addition of rooms specially
equipped for that purpose. Progress was also achieved
in accommodation and care for the elderly, as a result
of which the broad lines of some new types of buildings
started to become visible.
The ‘Gebouwcentrum Ziekenhuis’ (Hospital Building
Centre), a joint initiative of the Centre for Construction,
195

the Netherlands Hospitals Foundation, the Association
of Catholic Hospitals and the Royal Institute of Dutch
Architects [BNA), was officially opened on 28 February
1950 by the Minister for Social Affairs, A.M. Joekes. The
most important task of the centre was the creation of
standardised documents [standards documents or documentation
sheets) that would be used for comparative
purposes during the appraisal of new projects. The
standardisation of a specific feature, such as the nursing
unit, served the purpose of standardising its function,
dimensions and physical construction; only the last of
those three was seen as part of the task of the architect.
In the twenty years following the end of the Second World
War, the external appearance of the Netherlands changed
more drastically than in the preceding two hundred
years. The country’s population was also undergoing
unprecedented growth. Industrialisation, which was given
every support, was creating new social and economic
conditions. The country became subdivided into economic
core regions and regions that had fallen behind, in which
special revitalisation measures would barely be capable
of preventing further decline. An exodus took place from
the areas that had fallen behind to the areas in the west
of the country where the economic prospects were more
promising, however it was not the major cities that absorbed
the demographic growth as they had in the past, but the
smaller centres in the areas surrounding the major cities.
To use the jargon of urban developers, the city became
fragmented and lost its traditional qualities as a clearly
demarcated socio-economic entity situated within
clearly identifiable physical boundaries. The rapid
increase in car ownership encouraged the emergence of
commuter villages. The Netherlands became suburban.
It is only natural to assume that these dramatic
developments had their effects on the healthcare
sector. First and foremost, the number of services had,
at the very least, to keep pace with the growth of the
population. Hospitals and residential and care facilities
for the elderly would need to be incorporated within the
new patterns of settlement. This meant that the majority
of new establishments were set up in the commuter
towns and in the rapidly-growing suburbs.
An additional advantage that was particularly important
for hospitals was ease of accessibility via an expanding
network of main roads and motorways. As far as
psychiatric medicine was concerned, an attractive
landscape consisting of woods or dunes was still preferred.
Naturally enough, the new residential and working
environment that was created in record time had an effect
upon health. Prosperity-related complaints and stress took
their toll and fuelled a growing volume of criticism.
Increasing alienation came to be regarded as the most
significant effect of the changes upon elderly people. It
was thought that the most effective way of addressing
those specific problems affecting elderly people would
be to create a living environment specially adapted to
their needs. The culmination of this was a boom in the
construction of facilities for elderly people that was
unparalleled in any other country.
During and after the Second World War, the modernisation
of the construction sector in the Netherlands was in full
swing. This gave rise to a number of experiments.
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During the period of reconstruction following the end of
the war, many experiments were carried out into different
construction systems. These took the form of construction
methods that made use of standardised, mostly
prefabricated elements, almost always in combination
with a fixed system of dimensions. Initially, the most
important reason for these cumbersome and frequently
costly experiments was a shortage of skilled workers. Later
on, the emphasis shifted when it was realised that (mainly
residential) properties could be built much more rapidly
using this modern method of construction.
Standardised elements were also used in the construction
of care premises. On a practical level, the designs of
standardised components produced according to a fixed
system of dimensions had one thing in common: they
were geared up to allow further upscaling and made it
possible for basic units that were largely identical to be
combined. This meant that hospitals, care homes (which
already were larger than their counterparts in other
countries) and blocks of flats for the elderly became
even bigger. The distinctly modern appearance of the
Leyenburg Hospital (Leyenburg Ziekenhuis) in The Hague
Another form of standardisation involved the
prefabrication of entire sections of a building. This
method was typically used to construct showers, toilets
and kitchens, which took the form of fittings, as opposed
to a part of the building itself. Ultimately, it became
possible for entire buildings to be standardised. In the
public housing sector, that approach had already been
prevalent for a number of years, but with the exception of
fuel stations, bus shelters and other forms of motorway
architecture, it was found to be barely feasible when
constructing other types of buildings.
(designed by K.L. Sijmons) is due to the use of prefabricated
façade elements.
The standardisation of buildings is based on the assumption
that their function can be replicated. Local peculiarities
and the personal preferences of the clients play no part
in that regard. The number of programmes available for
the construction of housing was limited, but that applied
to a much lesser extent with regard to almost any other
function. Completely identical hospitals have been never
built, but hospitals that make use of a standard programme
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198

have certainly been constructed. The most well-known of
these are the five Wiegerinck hospitals in Utrecht, IJmuiden,
Heemstede, ‘s-Hertogenbosch and Oosterhout. These are
tower-on-podium hospitals in which the treatment unit is
located in the low-rise building and the outpatient departments,
with their own entrance, at right angles.
The use of the double-corridor system resulted in an
exceptionally compact ward block. Although the five
Wiegerinck hospitals are not completely identical, they
do in fact illustrate the ideal of the universal hospital
building package, of a hospital that paid as little heed as
possible to its surroundings and could be erected in any
arbitrary location. The idea that standardisation was a
way of saving large amounts of money turned out to be
unfounded. In the eyes of some researchers, the major
benefit of standardisation lay in the fact that the medical
staff had little influence on the design process.
The economic upturn reached its peak in the early 1970s.
The speed of developments within the care sector was
considerably greater than the average growth of the
country’s gross domestic product (GDP) and this was
particularly true in the case of hospitals and the provision
of residential facilities for the elderly. Critics complained
that the improvement in the level of healthcare was not
keeping pace with this disproportionate growth – care
was becoming more costly and more wide-ranging, but
not better. Though sufficient financial resources were
available for the moment, these criticisms gave rise to
questions regarding the path being followed.
In addition, the availability of finance was not the only,
or even the most important economic criterion: if the
care sector continued growing at the same pace, there
would soon be a shortage of personnel, especially of
nursing staff. Something therefore had to be done in
order to put an end to the unlimited growth that was
taking place. Restraint started to become an important
topic, especially in the hospital and elderly care sectors,
but also within the realm of psychiatric care. The second
major topic had to do with criticisms about the functioning
of the healthcare system. Those criticisms coincided with
growing protests against the welfare state in general.
Nowhere were those protests as vociferous as in the psychiatric
domain – this had always been the sector most directly
affected by opinions concerning people and society.
The impact of these criticisms immediately manifested
itself in the emergence of new architectural concepts.
The key words underlying these concepts were smallness
of scale, security and warmth. Social spaces needed to be
incorporated, in which people could spontaneously form
small, temporary communities. Contemporary functionalist
urban developments were accused of hindering such
processes by declaring that the narrow streets, alleyways
and squares that existed in older settlements were out of
date. Urban developments that predated the modern era
therefore became the most important source of inspiration.
This also applied to what were the most discussed
concepts within architecture and urban development
in that period: the principle of a support structure and
concepts of infill and interior fit-out.
By bringing about a separation between the industrially
fabricated support structure and from a fitting out package
designed to fulfil the needs of the user, the SAR hoped to
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reconcile the concept of personal freedom with that of
the modern-day industrial society. As long ago as 1969,
this distinction between a permanent structure and
a flexible interior already formed the basis of the new
guidelines that were published in the memorandum
entitled ‘Aspecten van het ziekenhuis van de toekomst’
(Aspects of the hospital of the future). Although the
majority of alternative plans for hospitals were found to
lack feasibility overall, the construction of small-scale
group facilities did take off within the realm of psychiatric
care. Group areas of this type were incorporated within
the structure of existing institutions. As far as providing
housing solutions for elderly people was concerned, the
construction of large complexes subdivided into smaller
units by small streets and squares gained in popularity.
embodied within the Hospital Provisions Act of 1971. This
provided for the creation of a Hospital Provisions Board
to look into the desirability of new buildings and to draw
up a national hospitals plan to that end. This resulted in
a regional distribution plan that quickly turned out to be
unachievable. The board was more successful in drawing
up criteria that construction plans were required to fulfil.
A committee constituted for that purpose achieved
greater success in putting together a set of criteria that
construction plans were required to fulfil, the elaboration
of which was outsourced to the hospital specialists
affiliated within the Foundation for Architects Research
on Health Care Buildings (Stagg). First of all, the Stagg
attempted to develop a standard programme, however
that turned out to be an overambitious objective.
Between 1953 and 1970, the cost of healthcare increased
by a factor of 10 (from 797 million to 7388 million Dutch
guilders). In that same period, the proportion of the
country’s national income that was spent on healthcare
rose from 3.3 to 6.4 percent. The proportion of healthcare
provided in hospitals (not including treatment from medical
specialists) increased from 32.8 to 43.8 percent. The
increase in costs was primarily a result of the increase in
the number of general hospitals and in the number of beds.
By the spring of 1969, there were 220 general hos pi tals
containing a total of 66,000 beds, which accounts for 5.1
per thousand of the population. Even the most optimistic
economic models did not hide the fact that healthcare was
well on the way towards becoming unaffordable.
It was hoped that if regulations were imposed governing
the construction of hospitals, the use being made of
hospitals would then decrease. That was the approach
Under the leadership of the Central Project Manager,
J.P. Kloos, the Stagg instead set out to investigate the
optimum dimensions of the various parts of a hospital.
Another important step in regulating supply was the
Healthcare Structure Memorandum presented by the
State Secretary for Public Health, J. Hendriks, in 1974.
This combined two strategies: the introduction of a
ladder structure (which meant that expensive equipment
could only be installed in hospitals) and regionalisation
(geographical distribution in accordance with the aims of
the Hospital Provisions Board). An important feature of
the Memorandum was the curbing of access to hospital
provisions: from that point onwards, patients had to be
referred by their general practitioner before they could
be admitted to a hospital. General practitioners therefore
became required to fulfil the role of gatekeeper. The
attempts by the Stagg to work on the development of
innovative hospital concepts gave rise to reflection on
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the subject of new principles. This led to the production of
the handbook entitled “Ziekenhuis Menselijk en Modern”
(The Humane and Modern Hospital), which was published
between 1969 and 1975 in the form of a loose-leaf
system and provided an accurate picture of the views
that were held in the 1970s.
It was the job of the architect to create the spatial
conditions in which this community could be created
and function. And that was something quite different
from ‘designing an efficient healing factory with a quasihumane
touch, such as shops in the reception area and
a reproduction on the wall’. The architect was expected to
create a humane environment in which the technological
perfection of medicine and healthcare could be combined
with the wellbeing of the patient. The task, therefore, was
to strive to bring about a synthesis between humane and
modern in the design of the building itself. In psychiatric
care, smallness of scale was the winning card, just like
low-rise buildings were in the case of hospitals. As a result
of the latest insights available, the Sint Willibrordusstichting
in Heiloo decided to commission new buildings. In 1975, this
led to a plan based on small groups of eight people. The first
tangible outcome was completed in 1980, relatively soon
after the original idea had been conceived. A typical feature
of many new building projects is the wordy and often
philosophically tinged justification that is provided for them.
As a starting point, a number of experts from the
professional field provided their views on the future of
healthcare. The expectation was that as a result of the
developments in medical technology, a smaller, hightech
core hospital would remain. After a short stay there,
the patients would be transferred to other facilities.
Municipal or regional treatment centres (satellites) would
be set up in order to provide outpatient assistance and
day treatment. The outpatient units became larger
and continued to form a part of the hospital as an
organisational entity (without necessarily forming a
physical part of it), and the importance of smallerscale
care provisions that needed to form either an
organisational or a physical part of a hospital increased.
Minor forms of hospital-related care could also be
delivered in care hotels (zotels), in sick bays or at home
in cooperation with home care organisations. R.B.M.R.
Bakker (a physician and medical director of the Westeinde
Ziekenhuis in The Hague) expected that the hospital would
increasingly be used as a shopping centre.
The distinction between a shopping street and hospital
would therefore become blurred. A more significant trend
involved the organisation of hospitals around medical
processes as opposed to medical functions. Different
categories of patients follow personalised courses of
treatment, as a result of which this trend resulted in the
identification of specific groups. In an ideal situation, the
medical specialisms would be distributed across these
groups, so that the hospital could be subdivided into
specialist clusters. That was not to be, however.
Healthcare buildings are among the most fascinating
architectural assignments. Their evolution commenced
around 250 years ago when hospitals and psychiatric
institutions deliberately began to distinguish themselves
by the way in which they were governed by their purpose.
Their function was to contribute to the recovery of the
patients who were admitted to them, and the architecture
was deployed as an instrument to make that
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202

203

204

possible. A natural, healthy environment was believed to
make an essential contribution to patients’ wellbeing and
to promote their recovery.
In the past few decades, however, developments have
arisen from the gradual shift towards a care system in
which market forces are coming to play a prominent
role. The magical formula that is constantly being
repeated is the replacement of supply by demand
regulation. In a liberalised market, the demand – in this
case for healthcare – determines the supply. Expenses
are not cut by limiting supply, but by competition,
and that competition will only increase as the market
takes on an increasingly open form. The supply was
characterised by an extensive system of permits
and restrictions governing the ability to run a care
institution, and the exemptions from them. The new
system is gradually doing away with the majority of
the restrictions. Institutions themselves are becoming
responsible for their real estate and are having to pass
the building and running costs on in the price of the
care. It is now a question of building flexible and above
all sellable buildings that function optimally without
wasting space. Although there are as many definitions
of optimal functioning as there are different parties and
perspectives, there is a consensus on the desirability of
reducing the number of parts of the building specifically
designed for their function to a minimum.
All institutions in the health care sector are being forced
to think about the usefulness and necessity of their
buildings – and therefore of architecture. Two extreme
positions can be discerned. On the one hand, there is the
view of architecture as a necessary evil, the costs of which
must be kept as low as possible. On the other hand, there
is the view that architecture is a business instrument
that directly influences the business results. Two aspects
play a major role in this regard: logistics and the way a
building is perceived and experienced by its users.
Any frustration of the logistical processes will lead to
high costs, while innovative concepts offer the potential
to achieve considerable savings.
As far as the architecture of hospitals is concerned, a
notable difference can still be observed, for the time
being, between the development of new concepts and
the implementation of the latest dinosaurs. The last few
years have seen the completion of complexes that were
developed from the mid-1990s onwards as the hospitals
of the twenty-first century.
The Martini Ziekenhuis in Groningen (2007), which
was designed by Arnold Burger from Burger Grunstra
Architecten Adviseurs, consists of two elongated
masses. One of those is characterised by its flowing,
serpentine shape, while the other takes the form of a
zigzag. These two masses are connected at two points.
A striking feature is the glass façade on the side of the
access road: this double façade endows the complex
with many of its salient characteristics. The hospital
itself is a model project demonstrating the use of
industrial, flexible and demountable architecture. In this
case, this is manifested in a system of partitions that are
easy to move in spite of the mass of cables and other
technical elements present. The interior design is by Bart
Vos (Vos Interieur) with a range of colours by the artist
Peter Struycken.
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The concept of a care boulevard is a popular one. This
consists of attracting medical and commercial activities
close to the hospital so that it blends with a complex of
businesses most closely resembling a shopping centre.
The concept of the care boulevard can therefore be
regarded as the medical equivalent of turning life
within society into a shopping experience. It is mainly
applied in general hospitals. The term ‘boulevard’ is
somewhat misleading: the combination of functions that
is characteristic of the classic boulevard is there, but
the physical form is completely different. The majority
of them are based on the shopping mall or medical
mini mall and often consist of an ensemble of separate
buildings – there are rarely any streets or squares.
The commercial look of a care boulevard seems to be
attuned to the transition towards a customer-oriented
form of service provision; in that sense, the care boulevard
represents the increasing influence of the belief in the
market-driven approach. Pragmatic considerations are
of greater importance: mainly thanks to the outpatient
units, hospitals attract a constant flow of customers,
which is attractive for the businesses on the boulevard.
The boulevard in turn provides additional revenue for
the hospital, especially when the hospital operates
the facilities itself or manages to conclude favourable
contracts with the private parties that operate them.
Moreover, a care boulevard forms a seamless transition
to normal forms of urban services, and that can help
to make the hospital manifest itself less as an isolated
bulwark. On the other hand, the concept stands or falls
as a result of a high degree of concentration. It forms
an enhancement to the conventional central hospital,
which is increasing in size even more as a result of this
addition. The one-stop medical centre implies that the
whole range of provisions, from non-medical to highly
medical, is clustered together.
While the previous decades were characterised by
an increase in scale, partly because it was the only
way to get the most out of the never ending stream
of mergers, the tide is now slowly turning. Of course,
there are many medical functions that can only be
accommodated properly in large hospitals. That is the
only place for complicated and hazardous interventions.
If multidisciplinary work is required, this therefore implies
that a concentration of different specialisations will
be available. Smaller institutions are also less suitable
as a location in which to provide training and conduct
research, so there will always still be a considerable
number of large complexes.
Nevertheless, the conviction that a large-scale facility
is always better has been made less obvious. The
search for ways of decentralising large hospitals has
been triggered by a variety of motives. First of all,
these included the consequences of the new building
legislation, which sharpens the differences between
the ‘hot floor’, offices and hotel functions and thereby
encourages the fragmentation of the building into
separate parts. Secondly, there is the awareness that
the classic all-under-one-roof hospital entails major
problems of logistics, is not flexible, generates a mass
of traffic, and combines things that have no functional
relationship to one another – all of which within an
inevitably institutional setting. Thirdly, the revolution
206

in the multimedia sector is increasingly making the
bridging of physical distances redundant. Information
can be exchanged at lightning speed, not only between
the departments within hospitals, psychiatric institutions
and nursing homes, but also between these institutions
and their outpatients.
Finally, the idea is gaining ground that small-scale clinics
are closer to the ‘client’, can play an important role in the
field of information and prevention, and are not hindered
by the massive scale and coldness of the large hospital
when it comes to approaching patients. At the same
time, however, these small-scale clinics can only take
over a small part of the range offered by larger hospitals,
which means that specialisation is inevitable. This
presupposes the existence of networks of care clusters,
extramural outpatient units and medical neighbourhood
and community centres.
As long ago as the 1990s, it was already thought that
the conventional central hospital would be reduced to a
small high-tech clinic. While the organisation of a large
hospital remains intact and may even be expanded with
provisions from other sectors, the accommodation is
spread over a large number of locations, which are in
intensive contact with one another thanks to the internet.
In an ideal situation, the internet enables patients to
exercise optimal control over the processes to which they
are being subjected, thereby reversing the relationship
between the customer and the provider of services –
a reversal that has already taken place in sectors of
society such as banking and travel agencies. In return
for the responsibilities and work that are transferred to
the customers, the latter gain more influence, especially
whenever they can choose from several providers at
different locations. Having a wide choice at their disposal
is a condition for the empowerment of patients.
While existing hospitals seem to be remarkably resistant
to the apparently growing demand for fundamental
changes, health centres with general practitioners,
physiotherapists and psychologists are springing up in
many different locations.
Many recently built hospitals are characterised by their de sire
to achieve high quality. This is in line with the rediscovery of
the potential of architecture referred to earlier and is also
encouraged by the revision of the system that obliges institutions
to develop strategies to ensure the optimal use of their
buildings. Similar trends can be seen in psychiatric institutions
and in housing for the elderly, where the same motives play
a role. The fact that quality can confer added value, both in
terms of use and – literally – in terms of accountancy is no
recent discovery; what is new is the discovery that optimum
profit can be derived from health care architecture.
As always, it all depends on the role of the principal.
Predicted growth and composition
of the population 2021 1502
According to the forecasts published in Primos 2021
(Population, households and housing need forecast to
2050), the population is expected to grow by around 1.3
million inhabitants in the period from 2021 to 2035. This
represents a growth of 7.4% in total. The strongest growth
is expected to take place during the next few years. Around
2034, the growth will still amount to over 70,000 inha bitants
per year. After 2035, current insights indicate that
population growth will still continue, but at a slower pace.
207

According to the forecast, the Netherlands will welcome
its 19 millionth inhabitant in 2038 and in 2050, the
country will be home to 19.5 million inhabitants.
Geographical map of the Netherlands/Primos.
Randstad
Northern flank
Eastern flank
Southern flank
Rest of the
Netherlands
Source: Primos 2021.
The 2021 forecast predicts an ongoing regional
differentiation. The strongest population growth in the
period up to 2035 is expected in the housing market
regions of The Hague (16%), Amsterdam (16%), Ede (14%)
and Utrecht (13%). In the northern flank, the strongest
growth is predicted to occur within the housing market
region of Lelystad (11%) and in the southern flank, the
population in the Eindhoven region is set to increase the
most (9%). The population of the housing market regions
in the part of the country designated as “Rest of the
Netherlands’ will either shrink or will experience only limited
growth. The Roosendaal housing market region forms an
exception, as its population is predicted to grow by 4%.
delays. For that reason, it is predicted that housing
production in 2021 and 2022 will be somewhat lower
than in preceding years. From 2023 onwards, housing
production is expected to increase strongly again. Part
of this will take the form of a catching up effect and part
of this prediction is based on the measured increase in
planned capacity, as well as upon changes in policy on
the part of government bodies.
However, it will take another few years before the
additional efforts expended by the State, provinces,
municipalities, and the clients responsible for
constructing buildings actually result in the delivery of
larger numbers of housing units. The Primos forecast
from 2021 predicts that in the second half of the 2020s,
the overall supply of housing units per year will increase
by over 80,000 dwellings per year. The peak is expected
to occur around 2026/2027, with a net growth of
between 85,000 and 90,000 dwellings. After that, current
insights indicate that production will fall as a result of
decreasing growth in the number of households and a
reduction in the shortage of housing.
As a result of the problems associated with nitrate
emissions and the coronavirus crisis, a certain proportion
of residential housing developments have suffered
208

In the period from 2021 to 2034 inclusive, a total of 1.16 million dwellings will be added to
the supply available and 168,000 will be removed. On balance, the supply of housing will
increase by just under 990,000 dwellings, which equates to an expansion of 12.4%. It is
expected that the housing shortage will peak in 2024 at 316,700, or 3.9% of the housing
supply and will then fall by 2.7% in 2030 and 2.0% in 2035. The housing shortage will
ultimately decrease even further to 1.4% in 2050.
Predicted population growth by component
120,000
100,000
80,000
60,000
40,000
20,000
0
-20,000
-40,000
2021 2023 2025 2027 2029 2031 2033 2035 2037 2039 2041 2043 2045 2047 2049
Natural growth
Balance of foreign migration
Source: Statistics Netherlands Population Forecast 2020-2070 (December 2020)
From 2022 onwards, the population is set to grow by more than 100,000 inhabitants a year
and in the period from 2021 to 2035, it is expected to increase by almost 1.3 million inhabitants.
This represents a growth of 7.4% in total. Around three quarters of this growth (78%) will
be the result of a positive foreign migration balance. Natural growth will therefore account for
less than one quarter of the growth that will take place. Between 2022 and 2026, the population
is expected to increase by an average of 105,000 inhabitants per year. This amounts to
an average population growth of 0.6% per year. The pace of growth will decrease over time,
however. In around 2034, population growth will be over 70,000 inhabitants, or 0.4%, a year.
The population growth predicted will not occur evenly across all age-groups. It is
predicted that the numbers of secondary school students (aged between 13 and 18 years)
and of older people in the potential working population (aged 45 to 67 years) will decrease
and will be even lower in 2035 than they were in 2021. The other age-groups will increase.
209

Predicted population figure by age-group (2021-2035-2050).
Up to 4 years
4-12 years
13-18 years
19-44 years
45-67 years
68-74 years
75 years or over
0
1 2 3 4 5 6 7
2021
2035 2050
Source: Statistics Netherlands
The trend underlying the number of households will depend on developments in
the composition of the population and the tendency, within that population, to form
households. This is governed by processes such as leaving the parental home, cohabiting
with a partner, seeking a divorce, suffering the death of a spouse and the transition to
intramural provisions (homes).
The majority of people live independently within a private household (the definition used by
Statistics Netherlands), however in the case of a small group of people, this does not apply.
They reside in an institution, such as a nursing home or care home, a children’s home, a
home providing an alternative to family-based care, a rehabilitation centre, a monastery or
convent or a penitentiary institution. Centres for asylum seekers are also included under this
category of intramural institutions. The group of people residing in an intramural institution
is also referred to as the institutional population. As a result of the ongoing ageing of the
population, the institutional population is expected to increase and to consist of 311,000
210

people in 2035. That number is 59,000 higher than in 2021.
Between 2035 and 2050, the size of that population is set
to increase by the same number of people once again.
an increase of 10.5%. Relatively speaking, this is a greater
increase than the growth in the population [7.4%) in that
same period: the average size of households will therefore
continue to decrease, from 2.14 in 2021 to 2.07 in 2035.
Trend with regard to the institutional population,
actual and predicted (2011-2050].
400,000
380,000
360,000
340,000
320,000
300,000
280,000
260,000
240,000
220,000
200,000
2011 2016 2021 2026 2031 2036 2041 2046
Actual
Primos 2021 Primos 2020
Source: CBS17 and Primos 2021 and 2020.
Forecasts also indicate that the number of single-person
households is also set to undergo a sharp increase by
592,000 [19%). In the first few years, around 60% to
70% of the increase in the number of people living alone
will consist of persons aged 65 or over. As the years
progress, that proportion will increase significantly. From
2030 onwards, the increase will consist almost entirely
of persons aged 65 or over. The increase in the number
of households during the period up to 2035 will consist
of: 4% single-parent families, 15% couples, 11% families
As far as the housing market is concerned, it is not the
population growth in itself that is of particular importance,
but the predicted increase in the number and the different
types of households. In the period from 2021 to 2034, the
total number of households is expected to increase by
848,000, from 8.0 million to 8.9 million, which equates to
and no less than 70% of people living alone. As far as
the period after 2035 is concerned, we will once again
witness a major increase in the number of people living
alone and that group will consist almost completely of
persons aged 75 years or over. The number of couples
with children will also increase from 2035 onwards.
Increase and decrease in the number of households by type and age (2021-2035 and 2035-2050].
700,000
600,000
500,000
400,000
300,000
200,000
100,000
0
-100,000
-200,000
15-29 30-64 65-74 75+
People living alone
15-29 30-64 65-74 75+
Cohabiting
15-29 30-64 65-74 75+
Cohabiting with
15-29 30-64 65-74 75+
Single-parent
Trend 2021 - 2035
Trend 2035 - 2050
Source: Primos 2021.
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212

16
INDOOR ENVIRONMENT - PARAMETERS
213

EVALUATION
Dynamic sunlight and daylight shading serves to reduce the amount of heat entering a building, which
in turn helps to reduce the amount of energy consumed in the building for the purpose of cooling 1601
and lighting 1602 . What is more, it can be assumed that using such systems will have a positive effect
on the people inside the building. The indoor environment parameters that relate to care buildings that
are affected by dynamic sunlight and daylight shading systems depend in part on the parameters
that apply to the productivity of users of office buildings 1603 , supplemented by suggestions made by a
variety of specialists in this field.
In the illustration below, these indoor environment
parameters pertaining to care buildings and the effect of
the various aspects of a sunlight or light shading system
are reproduced according to the way they interrelate.
An overview of the effect of dynamic sunlight and/
or daylight shading systems on indoor environment
parameters that affect the users of care buildings.
System
Solar shading
Daylight shading
Dynamic control
Motor
Temperature
Physical effects
Temperature
Radiation (asymmetry)
Daylight
Users of a building
On a sunny day, incoming rays from the sun play a
significant role in raising the temperature of a room. In
winter, this can have a positive benefit as less heating
needs to be provided by the heating systems. In the
spring and autumn, however, the sun can sometimes
give rise to unwanted excess heat and cause the
temperature inside a room to be too high or create a
situation in which a room requires excessive amounts
of cooling in order to guarantee the required room
temperature. If no cooling is available, outdoor solar
View
Luminance (glare)
Options for control
System noise
Long-term care
- Resident
- Staff
- Visitors
Hospital
- Patients
- Staff
- Visitors
shading will play an important part in preventing the
room becoming hotter.
If a cooling system is available, dynamic outdoor
solar shading will help to reduce the amount of energy
consumed by the room’s cooling system. In buildings
fitted with a cooling system and especially on extremely
warm days with outdoor temperatures exceeding 30°C
(when the cooling system is potentially insufficient
to keep the room at the required temperature), solar
shading is also important counteracting a rise in
temperature inside a room. In addition, the fact that the
sun is shining against the building’s façade can lead to
poor temperature distribution inside a room or building.
This is especially true if there is no separate means of
controlling the heating and cooling system for different
façades fitted with sizeable areas of glazing; the
temperature on the side of the building where the sun is
shining will be considerably higher than the temperature
on the side of the building situated away from the sun.
The use of dynamic solar shading can help prevent
overheating inside a building.
Radiation heat
The rays of the sun enter the room directly via the
glass. Depending on the solar factor of the glass and
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any solar shading facilities present, a certain proportion
of the sun’s rays will be kept at bay. Direct solar
radiation contributes to the heat load in the building
and causes the temperature at the place where the
solar radiation enters to feel higher as a result of the
solar rays shining on the mass of the building. This can
contribute significantly to the perceived temperature.
Solar radiation via a window creates a warm window
surface in the room. When window surfaces become
hot, the temperature in the room may be perceived to
rise because this large area is radiating heat. While solar
shading and light shading can each help to prevent
temperatures from feeling too high whenever the sun is
shining on a person, solar shading is generally the more
effective of the two.
Daylight
Daylight helps to reduce the amount of energy required
to produce artificial light and benefits people's wellbeing.
The amount of exposure to daylight that users of a
building receive depends on the design of the building
(e.g. the surface area of windows in the façade and the
orientation of the façade) and the location of the user’s
workstation inside the building (such as its distance from
the window and its orientation in relation to the window).
The daylight factor can be used to express the amount
of daylight at a particular place within a room; what this
factor does is indicate the ratio between the luminance
at a single spot inside the room and the luminance
occurring simultaneously outdoors. Dynamic regulation
and additional controls that allow users to control a
system of dynamic light shading and solar shading can
help optimise the amount of daylight inside a room.
View
Many people attach a great deal of importance to
having a good view, which is one of the reasons why it
is important to ensure that the glazed openings in the
façade are as generously proportioned as possible. The
quality of the view is also important: factors such as a
view of a green environment, nature or activities and
the ability to observe the weather or see the horizon or
landmarks located some distance away play a major
part in determining the quality of a view. Dynamic control
and additional controls that make it possible to control
a light or solar shading system can help preserve the
view while simultaneously optimising the amount of light
entering the room.
Glare from daylight and direct sunlight
The brightness of the daylight and the direction of
sunlight are constantly changing. On the one hand, this
dynamic has a positive influence on the experience and
wellbeing of individuals. On the other hand, an excess of
daylight and sunlight can also lead to visual discomfort,
for example when sunlight is shining into our eyes directly
or via a reflective surface or a screen, for example. It is
therefore important to ensure a good balance between
the incoming daylight and the ability to keep daylight and
sunlight out. Sufficient light shading and solar shading
can prevent glare caused by the incoming sunlight.
Options for control
Giving users the ability to control this for themselves
allows them to adjust the indoor environment to their
own needs. People will then be able to control the
amount of daylight and sunlight entering a room by
operating the dynamic sunlight and daylight shading.
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Giving them individual control has a positive effect with
regard to their satisfaction with the indoor environment.
This can partly be explained by the significant individual
differences in preference regarding temperature and
light conditions.
The extent to which an individual is able to control the
indoor environment can be expressed by referring to
three main parameters:
- The presence of controls: whether or not users
have the ability to adjust the indoor environment.
- Perceived control: the extent to which a person
feels that he/she is able to control the indoor
environment.
- Control exerted: specific actions that lead to an
adjustment of the indoor environment.
Research has shown that “perceived control” in
particular has a significant influence on the satisfaction
felt by the users of a building. 1604 Effective means of
controlling the indoor environment therefore contribute
towards a feeling of contentedness on the part of the
building’s users. 1605 In care institutions occupied by
people with a cognitive impairment, exercising control is
difficult or impossible for those residents. In such cases,
an effective, automatic control system that incorporates
an overrule facility to be operated by staff (or by family
members or visitors) is an important feature. A dynamic
control system for daylight and sunlight shading can
increase the ability of the user to adjust the amount of
daylight and the radiation of heat in a room.
Noise
A dynamic sunlight and daylight shading system that
emits a high level of motor noise can lead to complaints
regarding noise nuisance. In view of the fact that noise
is only produced while the system is being operated, the
duration of the nuisance is limited, though in the case
of automatic systems, noises can occur on a frequent
basis, depending on the weather conditions during the
course of the day. Nevertheless, it is important that the
noise level is not perceived as bothersome, so that the
solar shading and daylight shading systems can be used
as desired without disturbing other people. A quiet motor
can play a part in preventing noise nuisance.
Attributes of the building
The extent to which the use of an advanced sunlight
and/or daylight shading system will affect the
indoor environment will depend on the attributes of
Regulations and budgets of hospitals and buildings for long-term care. 1607
Buildings for long-term care
Hospitals
Ventilation1606 Building Decree 2012 6.5 l/s per person 12 l/s per person
Temperature
Netherlands College for
Hospital Design and Construction
20021607
Investment costs
Water installations:
Netherlands College for Hospital
Design and Construction 2002
Source: bba binnenmilieu
Residential function:
in accordance with standard residential construction (no requirements).
Nursing ward – somatic & psychogeriatric:
a minimum of 24°C in the winter and no more than 25.5°C in the summer
Nursing & care:
€112-€216 per m2
Mental healthcare and care for disabled people:
€65-€138 per m2
Nursing ward (general mental health and healthcare):
a minimum of 22°C in the winter and no more than 25.5°C in the summer.
Nursing ward – somatic & psychogeriatric:
a minimum of 24°C in the winter and no more than 25.5°C in the summer.
Hospital – general:
€ 368 per m2
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the building itself. In that regard, buildings used for
providing long-term care and hospitals differ from
one another with regard to the regulations governing
the indoor environment and the budgets available for
construction costs and installations. If a cooling system
of a sufficiently high capacity is available, sunlight
shading will have a less significant effect as a means
of preventing overheating than it would in a building in
which no or only limited cooling facilities are available.
The table contains details of the most significant
differences. What is striking in that regard is that the
requirements and budgets for buildings for long-term
care are considerably lower than those for hospitals.
Users of the building
When determining the effect of the indoor environment,
it is necessary to distinguish between users of buildings
for long-term care and users of hospitals, because the
primary target group of each type of building is different.
In buildings for long-term care, the primary occupants
are residents who live and receive care there, whereas in
hospitals, the primary users are patients who come and
stay in order to receive treatment and recover, often for
a relatively short time. In order to provide an insight into
the use of sunlight and daylight shading for the users of
healthcare buildings, it is relevant to chart the types of
activities undertaken by the users, how long the different
groups of users stay in the building and whether a
positive effect on the user is likely to contribute towards
the primary purpose of the building.
For both types of building, an overview is provided setting
out, in broad lines, the various types of users, their
activities and the length of their stay. The difference in
the length of stay of residents in care institutions for
long-term care and patients in hospitals forms a point of
attention.
As a result of the residents’ long and continuous stay,
the overall impact of the indoor environment is greater
than in the case of patients in hospitals (who usually
stay for an average of five days 1608 ).
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Overview – buildings for long-term care
Long-term care
Category Who Activities Length of stay Most important outcome measure
when assessing the quality of a stay
Residents
Elderly people, disabled people
and the chronically sick.
Living, daily activities,
recreation, sleeping.
Continuous, from several months
to years.
Quality of life.
Staff
Nurses, doctors, activity leaders
and support staff.
Care, help performing everyday
activities, supervision and support,
administration.
Working day, several days per week.
Efficiency with which tasks
are performed.
Visitors Family and friends of residents. Supporting the resident,
social interaction.
A few hours.
They experience contact
with the resident.
Overview – hospitals
Hospital care
Category Who Activities Length of stay Most important outcome measure
when assessing the quality of a stay
Patients
People who need to go treatment
or are recovering (from a variety of
conditions)
Recovery from sickness, undergoing
treatment, sleeping, daily activities
where possible.
Day (or part of a day) up to a few
weeks (sometimes months).
Recovery from sickness or treatment.
Contracting hospital-related
infections.
Staff
Nurses, doctors, other Care,
and support staff.
Care, treatments, diagnosis,
analysis, administration.
Working day, several days per week.
Efficiency with which tasks
are performed.
Visitors Family and friends of residents. Supporting the patient,
social interaction.
A few hours.
They experience contact with
the resident.
The outcome measure that has been selected in order
to chart the quality of the residents’ (the primary target
group) stay in buildings used to provide long-term care is
the quality of life. The World Health Organization (WHO)
has subdivided the quality of life into six aspects 1609
- Physical health (including pain, discomfort,
energy, sleep and fatigue).
- Psychological health (including feelings, cognitive
function, self-confidence).
- Independence (including mobility, everyday
activities, uptake of medicines).
- Social relationships (including contacts and support).
- Surroundings (including surroundings in the home,
financial situation).
- Philosophy of life (spirituality, religion, personal
beliefs).
The most important function of a hospital is to provide
professional healthcare. Depending on the type of care,
various outcomes are of importance. For patients who
stay in hospital for a longer period and for whom the
indoor environment therefore has the greatest impact,
the recovery time is a way of quantifying this.
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219

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17
LITERATURE STUDY
221

MODEL AND APPROACH
Research has been carried out in order to determine the effect of the aforementioned indoor
environment parameters on the users of healthcare buildings. In the case of long-term care,
the primary focus of the research involved the effect of quality of life based on the six individual
categories. In the case of hospitals, the focus relates to the recovery time and to wellbeing during
a patient’s stay. The study also set out to examine the extent to which these indoor environment
parameters affect the tasks and wellbeing of the staff.
Existing knowledge of the effect of the selected indoor
environment parameters on the users of healthcare
buildings has been charted, based on the scientific
articles that are available. A search was performed via
Google Scholar to identify studies that have analysed this
relationship. The search was carried out using search
terms, in which one of the search terms from two or three
of the categories was used in each case.
1. Healthcare: hospital, healthcare facility,
long-term care facility, elderly care, healing
environments, evidence-based design.
2. Indoor environment parameters: various
definitions relating to the topics in the overview.
3. Outcome parameters: aspects relating
to the outcomes.
Publications and articles referenced in one of the
relevant search results have also been read.
An overview of the relevant indoor environment para meters
and their possible effect on the users of care buildings.
Physical effects
Temperature
Radiation (asymmetric nature of)
Daylight
View
Luminance (glare)
Options for control
Noise emitted by installation
Users of buildings
Residents – quality of life:
- Physical health
- Psychological health
- Independence
- Social relations
- Environment
- Personal beliefs
Patients
- Recovery time
- Wellbeing during stay
- Contracting hospital
related infections
Staff
- Efficiency in the performance
of tasks
- Wellbeing
The outcomes of the literature study have been ranked
according to the physical effects.
Overheating
From the study of the literature, it emerged that increased
temperatures in healthcare buildings can give rise to
physical symptoms. An increased temperature can also
have a negative effect on a person’s sleep and behaviour,
can lead to an increase in mortality and can affect staff’s
performance of their work.
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An overview of the findings in connection with the effects of overheating amongst users of care buildings.
Category Overheating has an effect upon: Temperature range Substantiation#
Residents – long-term care
Physical health
Physical symptoms due to an inability to
adapt to heat (behavioural and physiological)
Temperature range is narrower in the case
of elderly people and the chronically sick. An
increase in respiratory conditions and certain
symptoms of dementia > ± 26°C.
Excess mortality During heatwaves. ***
Quality of sleep
A reduction in the quality of sleep at
**
temperatures of 24 to 26°C or above.
Psychological health Irritated behaviour or agitation Increased at temperatures of > 26°C. *
Independence
A decrease in physical functioning,
walking, balance
Social relations -
Environment -
Personal beliefs -
Patients – hospitals
Better at 20-22°C than at 27-30°C **
Recovery Sleep A reduction in the quality of sleep at
temperatures of 24 to 26°C or above.
Recovery time! Duration of stay -
Post-operative use of medicines (painkillers) -
Wellbeing Thermal comfort Greater diversity in the preference for a tempe -
rature by a wide target group (physical condition,
age), insulation provided by clothing and activity.
Healthcare buildings – staff
Work performance Productivity Staff’s own estimation of their productivity decreases
at higher temperatures (> 23 to 25°C.)
# Quality of substantiation: * ‘(very) moderately substantiated’, ** ‘reasonably substantiated’, *** ‘well-substantiated’
***
**
*
**
Residents – long-term care
PHYSICAL HEALTH
Nursing homes are mainly occupied by people who are elderly and chronically ill. These target groups
in particular have a reduced ability to adjust to heat. Ageing is accompanied by physiological changes
that affect heat regulation in the body and an individual’s own perception of temperature. As a person
ages, his/her ability to perceive cold and warmth by means of the nervous system is reduced. 1701 In
elderly people, the extent to which a person is able to use vasomotion (the narrowing and widening
of blood vessels) in order to regulate the amount of heat being emitted into the environment is
reduced. 1702 A person’s ability to transpire also reduces with age. 1703
These physiological changes contribute towards a situation in which elderly people are more sensitive
to extreme temperatures and therefore to overheating than younger people. A reduction in the perception
of thirst also poses a risk of dehydration during warm weather and a person’s use of medicines may
also affect his/her ability to regulate body heat. The fact that elderly people have a reduced ability
to adapt means that higher temperatures experienced during a heatwave contribute towards excess
1701, 1704
mortality and physical symptoms, especially amongst elderly people living in nursing homes.
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The effects of high temperatures are often more
severe in the cases of patients who are bedridden,
due to the fact that the “clothing insulation value” is
significantly increased by the mattress and the bed
linen. On a general level, higher temperatures (indication
> 26°C) also give rise to an increased risk of respiratory
conditions and symptoms of dementia. 1705 In the case
of patients who are bedridden, the temperature at which
that risk occurs is lower (22.5-25.5°C). 1706 Amongst
the risk groups and amongst residents of institutions
providing long-term care, it is important to prevent
overheating not only in order to combat those symptoms,
but also dehydration and excess mortality.
the room temperature is higher than 24 to 26°C, unless
ventilators are used for the purpose of cooling. 1708
These findings are borne out by an American study,
which demonstrated that sleep quality in elderly people
is also affected by the room temperature: the amount
of tossing and turning during the night increased as
the temperature in the bedroom of dwellings fitted with
cooling systems (air conditioning) operating at various
levels increased (within a range from 17.5°C to 30°C). 1709
In another study performed amongst older, healthy men,
it was found that they slept better at 26°C than at 32°C. 1710
The ability to control the maximum room temperature in
the bedroom can also contribute towards sleep quality.
Temperature also has an effect upon sleep. In care
buildings, a temperature that is too low or one that is
too high can have a negative effect on sleep quality. 1707
In general, the temperature immediately around the
body must be around 30°C in order to be able to sleep
comfortably. 1708 The temperature that a person perceives
to be a pleasant room temperature will depend on his/
her night attire, the duvet and the air speed. Assuming
that a person is wearing only lightweight clothing and
lightweight blankets are being used on the bed (with a
joint CLO value of 1), the quality of sleep will decrease if
PSYCHOLOGICAL HEALTH
Based on a field study conducted in nursing homes for
residents with dementia in Australia, it was possible to
chart the extent to which the indoor temperature to which
residents were exposed during two weeks had an effect
on agitated/irritable behaviour. Based on a questionnaire
completed by the care staff, the study found that the
number of hours during which the temperature lay
outside the comfort zone (higher than 26°C or lower than
20°C), contributed towards a higher score for agitated
behaviour. 1711 In elderly people, independent physical
functioning, such as walking and maintaining one’s
balance, is affected by the ambient temperature. 1705 At
22°C, participants achieved a better score with regard to
their walking speed, standing up from a seated position
and maintaining their balance than was the case at a
temperature of 27°C. 1712 In another study, elderly people
were able to cover a larger distance within the same period
of time at 20°C than they were capable of doing at 30°C. 1713
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INDEPENDENCE
In elderly people, physical functioning, such as walking
and maintaining one’s balance, is affected by the ambient
temperature. 1705 At 22°C, participants achieved a better
score with regard to their walking speed, standing up from
a seated position and maintaining their balance than was
the case at a temperature of 27°C. 1712 In another study,
elderly people covered a larger distance in the same period
of time at 20°C than they were capable of doing at 30°C. 1713
Patients – hospitals
Generally speaking, patients in hospitals need more sleep
in order to recover from their illness. 1714 The effect of
temperature on sleep quality, as described in the previous
paragraph entitled “Residents – long-term care” is therefore
also of importance in a hospital, both during the night,
as well as during the day. Studies have been found that
examined the effects of high temperatures on recovery
time or on the use of medicines. Not only elderly people,
but also the chronically sick (especially those with cardiovascular,
respiratory, musculo-skeletal conditions or
diabetes) are more sensitive to extremes of temperature. 1715
The temperature that patients perceive as neutral differs
significantly from person to person. This is not only due to
differences in age, bodily composition and BMI, but is also
the result of the diversity in the clinical picture of patients
and the difference in terms of activity and of the amount
of insulation provided by clothing (including bed linen). A
field study carried out in Saudi-Arabia, where the average
monthly outdoor temperature during the course of the year
varies between 24 and 34°C, observed that the room
temperature that patients perceive to be neutral varies
between 16.2 and 28.8°C. 1716 For about 75% of patients
and staff, that neutral temperature was lower than 24°C.
Preventing overheating is especially important in hospitals,
due to the sensitive nature of the target group.
Healthcare buildings – staff
In the case of staff working in the care sector, thermal
comfort is important as it enables them to carry out
their tasks effectively. 1707 Only one study could be found
into the effect of temperature on the productivity of
staff in the care sector. 1717 That field study, which was
carried out by Derks et al., found that the warmer the
temperature was perceived to be, the more negatively
individuals assessed the effect of the temperature on
their current activity. 1718 The study also demonstrates
that the temperature in the hospital examined (in
the Netherlands) varied by season: depending on the
orientation of the room, the average room temperature
in the summer was between 22.9 and 24.0°C, while in
the autumn, it was between 21.6 and 22.2°C. In summer,
nursing staff were more sensitive to heat. They also
found the temperature to be less pleasant and according
to their own assessment, their productivity was lower.
Only limited research has therefore been carried out
into the relationship between these two aspects in a
hospital setting, but it correlates with research carried
out into the effect of temperature on productivity in an
office environment. 1701 That research found that at room
temperatures in excess of 24 to 25°C, productivity when
performing office-related tasks decreases.
Heat radiation and radiation asymmetry
Within the literature, no studies were found that
specifically examined the effect of radiated heat on the
users of healthcare buildings.
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On a general level, it is the case that direct sunlight shining on a person contributes towards the
sensation of heat (increasing it) and the operational temperature (as a combination of air temperature
and the radiation component). Heat loss from the body is governed by principles comparable to the ones
that apply in the case of an increased air temperature.
As a result, the effects as described under overheating are exacerbated by any direct solar radiation a
person is subjected to. The importance of the radiation component is also borne out by research, in which
it was observed that a high radiation temperature outdoors forms a more effective predictor of mortality
during a heatwave than the air temperature. 1719 In the subsequent phase, both parameters will therefore
be combined and will be related to the operational temperature.
Daylight
The study of the literature found that daylight can contribute towards circadian rhythms and can
therefore have an effect upon sleep, pain relief and help bring about an improvement in mood amongst
residents and patients. In a hospital setting, exposure to daylight can also help to improve the recovery
time. The table below provides an overview of the findings in each target group.
An overview of the findings regarding the effect of daylight on the users of care buildings.
Category Daylight has an effect on: Daylight conditions Substantiation#
Residents – long-term care
Physical health The quality of sleep in elderly people The positive effect of daylight during the morning **
Creation of vitamin D Exposure to daylight **
Psychological health Mood. The positive effect of exposure to (day)light
(± > 400 lux)
Sundowning (restless behaviour A reduction in the ability to regulate
at the end of the afternoon) the ingress of daylight
Independence -
Social relations -
Environment -
Personal beliefs -
Patients – hospitals
Recovery Quality of sleep Improved when exposed to daylight due to the
orientation and structure of the room
Recovery time/duration of stay
Shorter in sunny rooms with lots of (morning)
daylight in comparison to rooms with dim
light conditions
Post-operative use of medicines (painkillers) Fewer painkillers taken by patients in sunny
rooms (intensity is 46% higher)
Wellbeing -
Staff – healthcare buildings
Work performance The likelihood of committing errors Reduced when the light intensity is high *
Work performance The positive effect of exposure to daylight *
Wellbeing Stress The positive effect of exposure to daylight *
Job satisfaction The positive effect of exposure to daylight *
# Quality of substantiation: * ‘(very) moderately substantiated’, ** ‘reasonably substantiated’, *** ‘well-substantiated’
**
*
*
**
*
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Residents – long-term care
As a result of physical changes to the eye, the amount of
light needed by elderly people is different to the amount
needed by younger people. Yellowing and a loss of
transparency in the lenses of the eyes reduce the ability
of elderly people to perceive light and contrast. A greater
intensity of light and a higher contrast are therefore
required in order to perform visual tasks. The amount
of time needed for the eyes to adapt may also increase
when passing from light to dark (or the other way around).
Significant differences also exist within the target group. 1720
PHYSICAL HEALTH
In many cases, the circadian rhythms of people suffering
from dementia are disturbed. 1721 Amongst other things, this
can lead to their pattern of sleep becoming disrupted and
give rise to symptoms of depression. Light can play a role
in the reduction of those symptoms by increasing the light
intensity during the day. 1722 A comparison between rooms in
nursing homes which benefit from or which lack a decent
amount of incoming daylight demonstrates that rooms
benefiting from daylight make a significant contribution
to the circadian stimulus. 1723 When conducting activities
with people suffering from dementia, even exposure to
(increased levels) of artificial light during the day can give
rise to an improved day and night rhythm. This effect is not
observed in persons with a visual disability. 1724
The effects of exposure to direct sunlight in the morning
on the sleep quality of elderly people in a care home has
been investigated in a number of field studies. Exposure
to direct sunlight on five mornings between 8.00 and
10.00 (study 1) or for one hour in the morning and
evening for six weeks (study 2) resulted in a significant
improvement of individuals’ own assessment of their
1725 and 1726
sleep quality and their alertness during the day.
A study involving residents with dementia, during which
the course of daylight was imitated in a care institution
by means of biodynamic lighting, partly underlines this
effect. The use of biodynamic lighting brought about a
reduction in sleepwalking and naps taken during the day
and an increase in the duration of sleep during the night. 1727
In another study, the intervention involving dynamic light
was found to have positive effects on sleep and mood
in one group of participants, but not in another group. 1728
Another study into the effect of high-intensity artificial
light (2500 lux) in the morning or for the entire day
showed an improvement in sleep in residents suffering
from dementia in a care home. 1729 Both the intensity
and the colour temperature of the light play a part in
the effect that it has upon residents with dementia: a
combination consisting of a high intensity of light and
a high colour temperature can contribute to a reduction
in restless behaviour and an improvement in circadian
rhythm. 1730 The effect on the quality of sleep brought
about by exposure to daylight in healthy elderly people
(not residing in an institution providing long-term care)
has been examined in a number of studies and explored
in a review authored by Lu et al. 1731
Based on the studies selected, the majority of the studies
identified substantiate the fact that daylight contributes
to the quality of sleep in elderly people.
In that regard, however, it is necessary to observe that
the effect was not confirmed in all studies and that it is
difficult to distinguish between the effects of daylight
and those of physical activity.
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229

In addition, the study by Aarts et al. 1732 did in fact
establish an association between the exposure to
daylight and sleep quality during the summer amongst
elderly people living at home. Though there was a
significant difference in the exposure to light in the
summer and the winter, there was no difference in
the quality of sleep between those two seasons.
Furthermore, daylight is of importance in the creation of
vitamin D. 1733 Vitamin D plays an essential part in bone
development and promoting health and is created via the
skin when it is exposed to ultraviolet B radiation.
Daylight contributes towards improved mood and helps
to reduce symptoms of depression. 1707 Research into
the effects brought about by exposure to light during
the day in patients suffering from dementia has shown
that it has a positive effect on emotions when a person
is exposed to a higher intensity of light (average daily
exposure > 417 lux). 1734 There is significant evidence
that a high intensity of light in the morning can lead to a
reduction in the symptoms of depression. 1735
Studies into the effects of light therapy in the morning
have confirmed that a high intensity of light in the morning
(two hours’ exposure to 2500 lux or 10,000 lux for half an
hour) reduces the amount of restlessness experienced by
elderly people suffering from symptoms of dementia. 1736,
1737
Daylight can also play a part in the “sundowning”
syndrome observed in persons with dementia.
Sundowning takes the form of an increase in irritable and
restless behaviour at the end of the afternoon/beginning
of the evening. Alongside increased restlessness when
carrying out activities, the decrease in the amount
of daylight may possibly play a part in “sundowning”
behaviour. 1720 In a field study carried out over a period of
one year, La Garce 1738 compared the behaviour of residents
in two rooms that were identical, except for the fact that
in one of the rooms, residents were able to control the
amount of daylight entering the space. In that study, it was
observed that in the room where the daylight was shaded
at the end of the afternoon, the residents displayed less
restless behaviour. Overall, exposure to high-intensity
light, especially in the morning, appears to make a positive
contribution to sleep quality and mood amongst elderly
people and people with dementia. The absence of a clear
day-night lighting cycle can have a negative effect on
health and wellbeing.
Due to the fact that people in care homes spend a great
deal of their time, or all of their time, indoors, this is a
focus for attention as far as that particular target group
is concerned. The amount of daylight entering a space
can play a significant role when it comes to achieving
the desired levels of light. 1722 However, the majority of
research carried out in care institutions has involved
the effects of artificial light instead of the effects of
daylight. Based on a literature review, Torrington and
230

Tregenza (2007) concluded that a building for long-term
care must have spaces that receive a high degree of
natural daylight, in which residents (including people
with dementia) are able to carry out activities on a daily
basis. 1720 These rooms must however have facilities
that make it possible to vary the amount of daylight, for
reasons including the need to combat glare.
Patients – hospitals
Exposure to daylight or high-intensity artificial light has a
positive effect on the day and night rhythm in patients and
1714, 1707, 1739, 1740
therefore on the quality of their sleep at night.
Daylight can also play a role in shortening the length of a
person’s stay in a hospital. 1741 Based on an analysis of a
medical database (85,000 patients), it was found that on
average, the stay in hospital of patients of different ages
and from different wards who had been placed in a bed
next to a window was shorter than the stay of patients
placed in a bed located next to the door. 1742
Comparable findings were also obtained in a study
carried out in a hospital in Korea, which demonstrated
that staying in a room with lots of daylight caused
patients’ stay in hospital to be shorter (16% to 41% shorter
on average) in a range of different departments. 1743
Especially rooms that received light in the morning were
found to have a positive effect. The positive effect of
morning light on a patient’s length of stay has also been
confirmed in the comparison between bipolar patients
in rooms with a view from the eastern façade and those
in rooms with a view from the western façade. 1744 In
patients without an indication of bipolar disorder, there
was no significant difference in the length of stay.
Research carried out by Beauchemin & Hays 1745 found that
patients being treated for a form of depression needed to
remain in hospital for a shorter period if they were staying
in a sunny room, compared to patients who were staying
in a darker room (16.6 compared to 19.5 days). Exposure
to sunlight was also found to have a possible effect in
terms of pain relief. The experiences of patients in sunny
rooms were compared to those of patients in more shaded
rooms. That comparison found that patients in the sunny
rooms needed fewer painkillers. 1246
Staff – healthcare buildings
The presence of sufficient light in the workplace is important
as a means of preventing errors. Various reviews have
concluded that a high light intensity in the workplace reduces
the number of errors 1714 and that daylight helps to enhance
performance in the workplace and reduces the number of
errors. 1707, 1747 Staff also associate daylight with a reduction in
stress. 1707 Nursing staff exposed to daylight for at least three
hours during the day experienced less stress and were more
content with their work, however the exposure to daylight had
no effect on burn-out score that was investigated. 1748
View
Based on an analysis of the literature, it was found that a
view of green spaces or nature can help to reduce stress
and pain and give rise to shorter recovery times in the
case of hospital patients. A view of nature also has a
positive effect upon staff in care institutions. Only limited
research has been carried out into the effects of a view
on the quality of life amongst residents of institutions
for long-term care, however the research that has been
carried out underline the importance of a view as a
means of ensuring the wellbeing of residents.
231

An overview of the findings regarding the effect of a view on the users of care buildings
Category A view has an effect on: Quality of the view, defined as: Substantiation#
Residents – long-term care
Physical health Pain reduction A view of nature or trees *
Psychological health Pleasure obtained from looking outside A view containing dynamic elements and
daily activities
Positive emotions and a reduction in stress A view of nature, trees, birds, flowers
and water
Independence -
Social relations
Social interaction by offering a place to
meet and a topic of conversation
Environment -
Personal beliefs -
Patients – hospitals
Recovery
Sleep
An interesting view of nature *
Recovery time/duration of stay A view of nature or trees **
Post-operative use of medicines (painkillers) ***
Wellbeing Stress A view of nature or trees ***
Staff – healthcare buildings
Work performance An improvement in work performance A view of nature *
Wellbeing A reduction in stress A view of nature *
## Quality of substantiation: * ‘(very) moderately substantiated’, ** ‘reasonably substantiated’, *** ‘well-substantiated’
**
*
Residents – long-term care
A large quantity of general research is available, which shows that a view of nature is one of the
factors that makes a positive contribution to human wellbeing. Only limited research has been carried
out, however, into the effect that having a view has upon people living in institutions for long-term
care and in specific target groups living there, such as elderly people with dementia. 1220 In a variety of
studies (performed outside the healthcare sector), natural elements, whether located nearby or further
away and a view of the horizon were identified as factors contributing towards the quality of the view.
Furthermore, the quality of the view in care institutions is additionally enhanced if that view includes
people going about everyday activities. In this context, small objects in the distance have a lesser
effect, due to the fact that residents have reduced vision. 1220
PHYSICAL HEALTH
A view of nature generally helps to divert patients’ attention away from pain and stimulates positive
emotions. 1714 No studies have been found which specifically charted this association and effect within
institutions for long-term care.
PSYCHOLOGICAL HEALTH
Based upon interviews conducted with elderly people with restricted mobility, it was concluded that
they enjoy having a view of the outside, especially if that view includes movement and change that
232

they are able to relate to themselves or to the world. 1749
The review by Torrington and Tregenza (2007) also
describes the added value provided by a view of people
carrying out everyday activities outdoors, especially if
the person observing them is confined indoors. 1720 In
another study, residents in a care institution said, when
interviewed, that they preferred windows with a view
of nature, compared to a view of buildings that did not
include any natural elements. 1750
This is borne out by research amongst elderly people
living in care institutions, which identified that elderly
people prefer an external environment with lots of
greenery, flowers, birds and water. 1714 In general, a view
of that type can help to elicit positive emotions. 1714 No
studies were identified that specifically examined the
effect of restriction of the view caused by sunlight or
daylight shading.
SOCIAL RELATIONS
In care institutions, the presence of windows with a view may
have a positive effect upon social interactions. An observational
study 1751 showed that people enjoy going to sit (whether
or not in groups) at the window, possibly and in part due to
the fact that this forms an accessible way of conversing with
one another about the things they can see, or because the
view itself summons up associations with the past.
Patients – hospitals
RECOVERY
A view of nature can reduce the perception of pain in hospital
patients. (e.g. 1714, 1741) The view offers a distraction, causing the
patient to pay less attention to the pain. The quality of the
view has an effect in this regard: patients who looked out over
trees recovered more effectively, experienced less pain and
required less pain-relieving medication than patients who
looked out at a wall. 1752
WELLBEING
Multiple studies have substantiated the fact that
a view of nature helps to reduce stress in hospital
patients. 1714,1741,1707 This not only applies in the case of
patients with a view of nature itself, but also in the case
of patients with a simulated view of nature. They felt an
increase in positive feelings and calm, whilst fear, anger
and negative emotions actually decreased when they
had a view of nature. A view of buildings lacking any
natural elements made a significantly less pronounced
contribution to the development of those positive effects.
Staff – healthcare buildings
In the case of staff in care institutions, a view of nature
also reduces stress and makes a positive contribution to
work performance and productivity. 1707
Glare caused by daylight and sunlight
Incoming sunlight can cause glare as a result of direct
sunlight or the of sunlight on a particular surface. This
can reduce visibility and can make it difficult to perform
an activity. reflection The presence of direct sunlight can
also be a cause of visual discomfort. On average, elderly
people have a higher sensitivity to discomfort resulting
from glare. Relatively few studies have specifically
examined the effects of glare in healthcare buildings.
The combination of visual discomfort and glare due to
sunlight and the positive aspects of sunlight underline
the need for adequate and dynamic systems controlling
the ingress of daylight.
233

An overview of the findings regarding the effect of glare upon the users of care buildings.
Category Glare has an effect on: Conditions resulting from sunlight Substantiation#
Residents – long-term care
Physical health Macular degeneration High levels of luminance *
Incidents involving falls Glare, poor visibility *
Visual discomfort High levels of luminance *
Psychological health -
Independence Performing activities independently Good visibility, without glare. *
Social relations -
Environment -
Personal beliefs -
Patients – hospitals
Recovery -
Wellbeing Visual comfort Level of luminance *
Staff – healthcare buildings
Work performance An improvement in work performance Glare, poor visibility. *
Wellbeing Visual comfort High levels of luminance *
# Quality of substantiation: * ‘(very) moderately substantiated’, ** ‘reasonably substantiated’, *** ‘well-substantiated’
Residents – long-term care
PHYSICAL HEALTH
As a group, elderly people are known to be sensitive to glare caused by high levels of
luminance and are therefore also prone to visual discomfort. 1720 Macular degeneration
occurs more frequently in elderly people (people aged 70 years or over) and high levels
of luminance (glare) can accelerate that process. 1753 Furthermore, good light conditions
(in which glare is prevented) are important as a means of ensuring good visibility. In care
institutions, smooth floor surfaces that reflect light are viewed as a problem. 1741 Preventing
glare or poor visibility caused by strong reflections on the floor can reduce the risk of
incidents involving falling. 1754 In addition to avoiding glare, it is important to ensure that the
intensity of light provided by daylight or artificial light is sufficiently high. Visual discomfort
caused by a high level of luminance (glare caused by a (locally) high level of reflected light)
can be prevented by making use of a system of dynamic light or sunlight shading. 1755
INDEPENDENCE
Good visibility is a necessity in order to perform a whole host of everyday tasks or
activities, such as walking, personal care, reading, writing and watching television. In
order to facilitate this, preventing high levels of luminance within the field of vision (but
outside the task area) can help people perform those activities well. 1720
234

Patients – hospitals
The review by Ulrich et al. states that “adequate light
conditions” contribute towards the overall contentedness
of patients with their stay in a hospital. 1714 The survey of
the literature by Eijkenboom identifies that luminance
plays a role in the perception of comfort amongst
patients and staff. 1747 Neither of these reviews however
found any specific studies that charted the impact of
glare on patients in hospitals.
Staff – healthcare buildings
Effective lighting is necessary in order to perform one’s
tasks correctly and to prevent errors. 1720 No specific
studies have been found that examined the effect of
glare resulting from daylight or artificial light on the
staff in healthcare buildings. On a general level, glare
gives rise to visual discomfort and can make performing
visually based tasks difficult.
Options for control
By providing options for control of daylight conditions in
the form of light and sunlight shading, conditions can be
adjusted in accordance with the needs and the external
conditions, depending on the activity and the target group.
In general, the ability to exercise control contributes
towards the contentedness amongst users, as long as
they are actually aware of the control being applied,
which means that the control must be both intuitive and
effective and must be capable of being operated in each
space or zone. In the case of care institutions, the ability
to control daylight is also desirable due to the residents’
and patients’ increased need for sleep.
235

An overview of the findings regarding the effect on users of care buildings
of options for the control of daylight.
Category Options for control have an effect on: The extent of options for control Substantiation#
Residents – long-term care
Physical health Quality of sleep The ability to shade out light *
Psychological health
A reduction in “sundowning”
(restless behaviour)
Independence - -
Social relations - -
Environment - -
Personal beliefs - -
Patients – hospitals
The ability to regulate incoming
daylight at the end of the afternoon
Recovery Quality of sleep The ability to shade out light *
Wellbeing Stress The ability to control daylight **
Staff – healthcare buildings
Visual comfort
Work performance Activities Control over daylight *
Wellbeing Visual comfort *
# Quality of substantiation: * ‘(very) moderately substantiated’, ** ‘reasonably substantiated’, *** ‘well-substantiated’
*
Residents – long-term care
The provision of options to control sunlight and light shading can contribute towards
the creation of conditions that are desirable at that point in time. In care institutions
providing long-term care, this can pose a problem in some cases, such as in situations
involving people suffering from dementia or another cognitive limitation. In some cases,
the options for control will need to be exercised by staff, family members or visitors
and the effectiveness of these will therefore depend on the ability to shade out the
amount of light required by the patients. One option, of course, is for such facilities to
be operated automatically.
PHYSICAL HEALTH
The ability to exert an adequate level of control over the light situation can help to create
a good sleeping environment for residents. 1714
MENTAL HEALTH
Regulating “daylight” at the end of the day can play a part in reducing what is known as
the “sundowning syndrome”. This takes the form of an increase in irritable and unsettled
behaviour at the end of the afternoon/beginning of the evening. 1720
236

Having the ability to shade out daylight at the end of
the afternoon can have a positive effect in preventing
a restless end to the day. 1738
Patients – hospitals
The absence of options for patients to control the indoor
environment can lead to stress and frustration. Providing
a means of controlling daylight is one of the factors
with the potential to make a positive contribution in
this context. 1741 According to the study by J.H. Choi, L.O.
Beltran and H.S. Kim, 1743 providing a means with which to
control daylight is of importance as a means of ensuring
contentedness amongst patients and as a means of
combating uncomfortable conditions while still ensuring
that sufficient light is present in the room. In addition,
it also contributes to the feeling that they are living in
“normal surroundings”, which in turn will help to reduce
stress. 1707 What is more, the ability to control light (both
daylight and artificial light) in a hospital environment can
also be desirable due to the need, amongst patients, for
In order to facilitate this, there will need to be a facility to shade
out daylight at the time when a patient wishes to sleep.
Staff – healthcare buildings
The ability to control daylight has a positive effect upon staff
in care institutions. 1707 It offers the possibility to create light
conditions that are desirable at that point in time for the
tasks being performed and/or that ensure visual comfort.
Little research has actually been carried out that focuses
specifically on the importance, for staff, of the ability to
control daylight and temperature in care institutions.
Noise
The use of sunlight and light shading gives rise to a
periodic increase in the level of noise. In care institutions,
high levels of noise can give rise to restlessness and
disrupted sleep. The effect of noise in care institutions is
reasonably well substantiated, however the role of noise
resulting from sunlight and light shading in that regard
has not been specifically charted.
an above-average amount of sleep. 1714
237

238

239

An overview of findings regarding the effect of noise on the users of care buildings.
Category Noise has an effect on: Noise conditions Substantiation#
Residents – long-term care
Physical health Reduced quality of sleep Noise levels >30 dBa *
Psychological health Unsettled behaviour and confused behaviour An increase in noise level **
Independence - -
Social relations Social interaction Reduced when noise levels are high *
Environment - -
Personal beliefs - -
Patients – hospitals
Recovery Reduced quality of sleep Noise levels >30 dBa **
Increased heart rate and blood pressure Increased noise levels *
Post-illness recovery *
Wellbeing Stress Increased noise levels *
Discontentedness Increased noise levels *
Staff – healthcare
Work performance Medical errors Unexpected noise *
Wellbeing Sleep and health Noise levels in the workplace *
Stress and fatigue Noise levels in the workplace *
# Quality of substantiation: * ‘(very) moderately substantiated’, ** ‘reasonably substantiated’, *** ‘well-substantiated’
Residents – long-term care
Lower noise levels are associated with a higher quality of life. 1756
PHYSICAL HEALTH
On a general level, noise forms an important factor than can have a negative effect on
the quality of sleep. The WHO recommends a value of 30 dBa, in order to prevent an
unsettled night, but also states that lower levels of noise can also have a negativ impact.
No clear indications have been found that noise has a greater impact on sleep in people
suffering from dementia. 1757
PSYCHOLOGICAL HEALTH
In people suffering from dementia, high noise levels can lead to an increase in aggressive,
disruptive and confused behaviour. 1757, 1758 It is necessary to establish what constitutes an
optimum level and represents a pleasant level of background noise (type and intensity).
SOCIAL RELATIONS
High levels of noise are also associated with reduced social interaction. 1758 In one study,
moderate levels of noise contributed towards social interaction in people suffering from
dementia, 1759 while in a different study, high levels of noise actually had a negative effect. 1760
240

In this regard, establishing a good balance in the form of a
pleasant level of background noise is also of importance.
Patients – hospitals
RECOVERY
Noise is an important factor that has a negative effect on
sleep in hospital patients. 1714, 1761 High levels of noise give rise
to more unsettled sleep. As a result of the stress induced by
noise, noise can also give rise to an increase in a person’s
heart rate, blood pressure and breathing and can lead to
lower blood saturation levels. 1762 Increased noise levels can
also have a negative impact on patients’ recovery. 1741
WELLBEING
Noise is often a problem in hospitals.
Three major factors contribute towards this:
- The amount of equipment and number of people
who generate noise .
- The hardness of the materials from which the
finishes in the building are constructed.
- The fact that several people are staying in one room. 1762
Noise is one of the aspects that patients complain about
most frequently. 1707 Noise can also lead to high levels of
stress and thereby increase psychological and physical
stress. 1762 The World Health Organization has drawn up
guidelines with regard to noise levels in patients’ rooms:
a background noise level not exceeding 30 dBa and noise
peaks of short duration not exceeding 40 dBa. 1763
Staff – healthcare
In a non-medical setting, high levels of noise can cause
a distraction and therefore have a negative effect on
work performance. 1714 Unexpected noise in particular has
a negative influence; when performing complex tasks,
it can lead to an increase in errors. In the case of care
buildings, the available evidence is less well substantiated,
even though there are indications distractions caused by
unexpected noise can cause people to commit errors. 1714
In hospitals, noise can have a conflicting effect: on the one
hand, there is a need for concentration, while on the other
hand, noise emitted by people or equipment indicates that
they require attention at that point in time. 1764 On the basis of
the current studies, it is impossible to draw conclusions regarding
the extent to which noise and acoustics in a hospital
affect the work performance of its staff. 1764 Furthermore, high
levels of noise in hospitals may possibly have a negative effect
on health complaints amongst staff and cause unsettled
sleep. 1747 Lower levels of noise in the workplace are associated
with reduced stress and a reduction in fatigue. 1707
Conclusions
On the basis of the study of the literature, it can be
concluded that the indoor environment does have an
effect on the users of healthcare buildings and that
dynamic sunlight and light shading is able to make
a contribution in that regard by optimising certain
parameters that form part of the indoor environment. The
findings applicable to the primary users of those buildings,
i.e. residents of institutions for long-term care and patients
in hospitals, have been summarised and illustrated.
Long-term care
In the case of residents in buildings used for the provision
of long-term care, a distinction has been made with
regard to the effects upon a variety of areas that form
part of the quality of life.
241

Operational temperature
Daylight
1, 2, 3
1
1
3, 4
1, 4
Physical health
1. Physical complaints 5. Pain symptoms
2. Mortality
6. Likelihood of falling
3. Sleep
7. Retina
4. Vitamin D 8. Visual comfort
Physical health is affected by factors such as the
operating temperature, daylight and incoming sunlight,
the view, glare and the ability to operate dynamic light
shading systems. Psychological health can also be
affected to a certain degree by the temperature, by
exposure to daylight, the view and the ability to operate
a light shading system. The temperature and the degree
of glare can also have an effect on the independence of
residents. Finally, the view and the level of noise are
parameters that affect social interactions between residents.
An overview of the effect of individual indoor
environment parameters and the effect upon
the quality of life of residents of care institutions
for long-term care.
View
seen that recovery is affected 1 by the temperature,
6, 7, 8
Glare
4. Stress
ingress of daylight and 2 sunlight, the view, options for
3
1. Physical functioning, walking, balance
control
Options
and
for
noise.
control
Wellbeing, such 2. as Performing stress activities and independently comfort,
1
Social relations
is affected Noise by all of the factors investigated, 1. Social interaction with the
exception of daylight (with regard to which it is necessary
to state that no study has been found that specifically
set out to investigate that association).
Operational temperature
Daylight
View
Glare
Options for control
Noise
5
2, 4
3
1
1
1
1, 2, 3
1
2, 3
3
2, 3
2
1, 2, 3
2
Psychological health
1. Irritable behaviour and restlessness
2. Mood and enjoyment
3. Sundowning
Independence
Recovery
1. Sleep
2. Recovery time/duration of stay
3. Use of medicines
4. Increased blood pressure and heart rate
Welbeing
1. Thermal comfort
2. Stress
3. Visual comfort
4. Discontentedness
Operational temperature
Two comments regarding the illustration:
- The absence of an arrow in the diagram can also
mean that the relationship has not been investigated.
1
Recovery
- The thickness of the line reflects the extent to which
Hospitals
Daylight
View
Glare
Options for control
Noise
Operational temperature
Daylight
1, 2, 3
1
1
3, 4
1, 4
5
2, 4
1
6, 7, 8
2
3
3
1
1
1
1, 2, 3
Physical health
1. Physical complaints 5. Pain symptoms
2. Mortality
6. Likelihood of falling
3. Sleep
7. Retina
4. Vitamin D 8. Visual comfort
Psychological health
1. Irritable behaviour and restlessness
2. Mood and enjoyment
3. Sundowning
4. Stress
Independence
1. Physical functioning, walking, balance
2. Performing activities independently
Social relations
1. Social interaction
1. Sleep
2. Recovery time/duration of stay
View
2, 3
4. Increased blood pressure and heart rate
3. Use of medicines
the relationship has been substantiated (the thic-
2
ker the line, the more substantiated it is).
Glare
Options for control
Noise
1
3
2, 3
1, 2, 3
Welbeing
1. Thermal comfort
2. Stress
3. Visual comfort
4. Discontentedness
2
In the case of patients in hospitals, the topics of recovery
and wellbeing during a stay were examined. It can be
RELEVANCE OF OUTCOMES RESULTING FROM THE USE OF
DYNAMIC SUNLIGHT AND LIGHT SHADING SYSTEMS
Dynamic sunlight and light shading systems can therefore
contribute towards the quality of life of elderly people in
care homes and to the recovery of patients in hospitals.
In various studies, the magnitude of the effects caused
by indoor environmental conditions has only been
investigated to a limited degree. As a result, the benefit that
the indoor environment provides to the users cannot be
quantified. It is however possible to describe the effects.
Sunlight and light shading systems can make a
demonstrable contribution to the process of optimising the
indoor environment in care buildings. The characteristics
of the dynamic sunlight shading system, of the dynamic
light shading system and of a motor, if used, have an
effect in that regard, however the relative effect will
differ, depending on the characteristics of the building
242

(including situations in which the façade of rooms is oriented in a different
direction and in which a cooling system is available). The desired physical
consequences of the system are shown in an illustration. In an optimal
situation, a good balance can be found between the various parameters.
A flowchart showing, on the left, the various components of the intervention, in the middle, the desired indoor environment
parameters and on the right, the effect on users of the building in the case of buildings for long-term care.
System
Desired physical outcomes
Users of buildings
Residents:
Building & features
Sunlight shading
Daylight shading
Dynamic control
Motor
Prevention of overheating
(a combination of air temperature and radiation)
Optimisation of daylight
Retention of view
Prevention of glare
Options for control
Prevention of noise nuisance
Physical health
Psychological health
Independence
Social relations
Staff:
Work performance
Wellbeing
243

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1709 A. A. Williams, J. D. C. Spengler, A. J. G. P. en
J. G. Cedeno-Laurent, „Building vulnerability
in a changing climate: indoor temperature
exposures and health outcomes in older adults
living in public housing during an extreme heat
event in Cambridge, MA,” International journal of
environmental research and public health, nr.
16(13), p. 2373, 2019.
1710 K. T. K. &. M. K. Okamoto-Mizuno, „Effects of
mild heat exposure on sleep stages and body
temperature in older men,” International journal of
biometeorology, nr. 49(1), pp. 32-36, 2004.
1711 F. Tartarini, P. Cooper, R. Fleming en M.
Batterham, „Indoor air temperature and agitation
of nursing home residents with dementia,”
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1712 U. Lindemann, A. Stotz, N. Beyer, J. Oksa, D. A.
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indoor temperature on physical performance in
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14(2), p. 186, 2017.
1713 A. Stotz, K. Rapp, J. Oksa, D. A. Skelton, N. K. J.
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heat exposure on blood pressure and physical
performance of older women living in the
community—a pilot-study,” International journal
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1714 R. S. Ulrich, C. Zimring, X. D. J. Zhu, H. B. Seo, Y. S.
Choi en A. ... & Joseph, „A review of the research
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Journal, nr. 1(3), pp. 61-125, 2008.
1715 C. Carmichael, G. Bickler, S. Kovats, D. Pencheon,
V. Murray, C. West en Y. & Doyle, „Overheating and
hospitals: what do we know,” Hosp Adm,, nr. 2(1),
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1716 B. S. Alotaibi, S. Lo, E. Southwood en D. & Coley,
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en A. Satlin, „Sundowning and circadian
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2001. Invloed binnenmilieu op gebruikers van
gezondheidszorggebouwen 30
1722 P. Boyce, C. Hunter en O. Howlett, „The benefits
of daylight through windows.,” Troy, New York:
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and Environment, nr. 150, pp. 245-253, 2019.
244

1728 O. M. Giggins, J. H. K. Doyle en M. George,
„The impact of a cycled lighting intervention
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Gerontology and Geriatric Medicine, nr. 5, 2019.
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1743 J. H. Choi, L. O. Beltran en H. S. Kim, „Impacts of
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1744 F. Benedetti, C. Colombo, B. Barbini, E. Campori
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Invloed binnenmilieu op gebruikers van
gezondheidszorggebouwen 31
1746 J. M. Walch, B. S. Rabin, R. Day, J. N. Williams,
K. Choi en J. D. Kang, „The effect of sunlight
on postoperative analgesic medication use: a
prospective study of patients undergoing spinal
surgery.,” Psychosomatic medicine, , nr. 67(1), pp.
156-163, 2005.
1747 A. Eijkelenboom en P. Bluyssen, „Comfort and
health of patients and staff, related to the
physical environment of different departments in
hospitals: a literature review,” Intelligent Buildings
International, 2019.
1748 M. K. Alimoglu en L. Donmez, „Daylight exposure
and the other predictors of burnout among
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1749 C. Musselwhite, „The importance of a room with a
view for older people with limited mobility,” Quality
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1750 A. R. Kearney en D. Winterbottom, „Nearby
nature and long-term care facility residents:
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2006.
1751 G. E. Chalfont, „Connection to nature at the
building edge: towards a therapeutic architecture
for dementia care environments,” Doctoral
dissertation, University of Sheffield, 2006.
1752 R. S. Ulrich, „View through a window may
influence recovery from surgery,” Science, nr.
224(4647), pp. 420-421, 1984.
1753 J. R. Carpman en M. A. Grant, Design that
cares: Planning health facilities for patients and
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1754 L. Edwards en P. Torcellini, Literature review of the
effects of natural light on building occupants.,
2002.
1755 J. H. Choi, L. O. Beltran en H. S. Kim, „Impacts of
indoor daylight environments on patient average
length of stay (ALOS) in a healthcare facility,”
Building and environment, nr. 50, pp. 65-75, 2012.
1756 L. J. Garcia, M. Hébert, J. S. I. Kozak, S. E.
Slaughter, F. Aminzadeh, ... en M. Eliasziw,
„Perceptions of family and staff on the role of the
environment in long-term care homes for people
with dementia.,” International Psychogeriatrics,
nr. 24(5), pp. 753-765, 2012.
1757 G. Marquardt, K. Bueter en T. Motzek, „Impact of
the design of the built environment on people
with dementia: an evidence-based review,” HERD:
Health Environments Research & Design Journal,
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1758 H. Chaudhury, H. A. Cooke, H. Cowie en L. Razaghi,
„The influence of the physical environment
on residents with dementia in long-term care
settings: A review of the empirical literature.,” The
Gerontologist, nr. 58(5), pp. 325-e337, 2018.
1759 J. Cohen-Mansfield, K. Thein, M. Dakheel-Ali en M.
S. Marx, „Engaging nursing home residents with
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pp. 471-48, 2010.
1760 J. Garre‐Olmo, S. López‐Pousa, A. Turon‐Estrada,
D. Juvinyà, D. Ballester en J. Vilalta‐Franch, „
Environmental determinants of quality of life in
nursing home residents with severe dementia.,”
Journal of the American Geriatrics Society, nr.
60(7), 2012.
1761 M. Rashid en C. Zimring, „A review of the
empirical literature on the relationships between
indoor environment and stress in health care
and office settings: Problems and prospects of
sharing evidence,” Environment and behavior, nr.
40(2), pp. 151-190, 2008.
1762 Ulrich en Zimring, „The Role of the Physical
Environment in the Hospital of the 21st Century: A
Oncein-a-Lifetime Opportunity,” Concord, CA: The
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Organization, „Guidelines for community noise,”
1999.
1764 J. Reinten, „Exploring the effect of the sound
environment on nurses’ task performance:
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2020
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248

PRODUCTIVITY
AND SUSTAINABILITY
GO HAND IN HAND
IN ECOLOGICAL
AGRICULTURE
In this supplement Ruud Sies and Hanneke van Hintum take the reader on a journey to the world
of sustainable agriculture and horticulture, where principles are used to make food production healthier,
safer and more efficient and resilient worldwide. In the summer of 2020 they travelled to Romania
and made a fascinating documentary about their trip.
Maramureş
Máramaros
Co-ordinates: Lat. 47º57’0’’ N, long. 23º39’0’’ E
Land area: 10,722 km2
Inhabitants: (2001) 825,000
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High Nature Value Farmed Landscapes of Romania
Several of the most important farmed landscapes in the European
Union that have been designated “High Nature Value Farmed
Landscapes” are found in Romania.
These small-scale tended landscapes are of great economic
importance. Romania has 3.9 million agricultural enterprises,
most of them family-run. Around a million farms of between one
and ten hectares cover a total of 3.1 million hectares, which is
approximately 20% of all Romanian arable land. They are partially
self-sufficient farms that produce food for private consumption
and for local sale.
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253

254

The haystacks of Maramures
Anyone taking an early morning stroll across the grassy slopes of
Maramures would think they had entered a fairy tale. This manmade
landscape is the perfect symbiosis between nature and human
activity, and within it, one of the most important treasures of the
cultivated world.
Maramures has one of the most extensive flower-rich grasslands
remaining in lowland Europe. This region, essentially unchanged for
centuries, combines low-intensity agriculture with an abundance of
flora and fauna.
This is one of Europe’s last-remaining areas of inhabited, semi-natural
landscapes. Importantly, it is a place where biodiversity is even richer
than in many wilderness areas.
Fifty species of grass can be found here on just a few square metres
of meadow, and among the grasses a particularly rich variety of plants
and herbs grows, like sorrel, snapdragons, gentians, marjoram, thyme
and meadow sage.
Hardly any fertilizers are used nor any herbicides or pesticides. These
poorly off farmers simply cannot afford them, but also deeply distrust
these products.
This floriferous miracle is not maintained by nature alone - it is nature
worked by human hands.
255

More than 60% of the milk produced in Romania comes from farmers
who own just two or three cows. Hardly any of it leaves the farm as
milk; most of it is processed right there into soft cheese, butter and
crème fraîche.
There is a simple piece of arithmetic known to every farmer in the
area: a cow eats four tonnes of hay over winter, which takes five
hectares of meadow to produce. Mowing by hand, one man with a
scythe needs ten warm summer days to rake that amount together.
But fortunately, nobody needs to do it on their own. The ancient
ritual of haymaking is an annual event that brings the whole family
together. Only with hay is it possible to keep cows, and only with
milk from cows is human life sustainable in this region.
Here everything revolves around transferring nutrients from meadow
to plate. And that explains why in these valleys hay is the measure
of all things. A stretch of grass needs to be attended to ten or more
times over. First it is mown, then the mown stalks are raked into
small piles that absorb the dew overnight before being spread out
again to dry in the sun the following day. It is then turned, to dry the
lowest layers, and collected into the classic haystacks right there
in the field.
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261

It is a little-known fact that Romania has the highest level of selfsufficiency
in Europe. The millions of small farms are some of the last
remaining areas with traditional agriculture on the European continent.
But this traditional way of life is under threat because multinational
companies and banks consider it to be a good investment. Small
farmers in Romania are confronted with the fact that their houses,
culture and livelihood are being taken away from them, as communal
land is sold to foreign companies. The only option they are left with is
to work for big agribusiness companies as landless labourers.
Estimates suggest that around a million hectares (10% of all the
farmland in Romania) are now owned by foreign capital.
Most traditional farmers are poor and at the same time they feel
deeply proud of the beauty of the land they inherited.
They regard it as their job, their duty, to pass it on to the younger
generations. The average income of a farming family is about 4,000
euros per year.
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Every household distils its own Horinca from berries, plums, apples
and cherries or whatever else the orchard provides. Farmers often
make their own brew, but in many villages the drink is still traditionally
prepared collectively. Once a year, the fruit is collected in large vats
after the harvest and distilled by the whole village.
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The importance of small-scale family businesses is not purely economic. Sustainable land
use, the conservation of biodiversity and other ecological, social, cultural and economic
values are crucial benefits of High Nature Value agriculture.
Small-scale agricultural landscapes are resilient and quicker to adjust to climate change
and other environmental challenges. In other words, they present opportunities to make
farming more flexible.
They are strongly associated with low-CO2 emissions, low-carbon, short food-supply chains
based on local and direct sales.
Family farms in Romania are an important source of agrobiodiversity. Both fodder
crops, including grasses and clovers, and all kinds of varieties of vegetables and fruit
are of crucial importance for food security. And equally important: they ensure that the
countryside is resilient to future climate change.
Natural forests and permanent semi-natural grassland both function as substantial
carbon sinks, benefitting air quality and providing a stabilising factor for the climate.
Along with the low energy consumption and short supply chains that characterise
traditional farming, these landscapes and systems have the capacity to reduce CO2
emissions, thus limiting climate change.
270

In developing our ideas, we have been assisted
by the Rotterdam based consultancy firm bba
binnenmilieu. They have helped us with our desk
research and assisted us in developing the model
described in this book.
bba binnenmilieu specialises in everything
related to the indoor environment and how it
affects people. They are very experienced in
providing insight as to the impact the indoor
space has on productivity. They have written the
“Kentallen binnenmilieu en productiviteit” report,
executed on behalf of Platform31.
Marije te Kulve, the research study's project leader,
is a consultant with bba binnenmilieu, and a specialist
in the field of how temperature and light affect
humans. A graduate of the Faculty of Architectural
Engineering at the Technical University of Eindhoven,
she spent her PhD trajectory with the department
of Human biology at Maastricht University where she
carried out research into the interaction between
light and temperature perception. One of the subjects
she explored was the influence of temperature and
light on alertness. Together with her colleagues at
bba she has examined the productivity effects of the
use of solar and daylight shading in offices for Somfy.
The supplement in the back of this book is a good
example of a successful combination of productivity
and sustainability. Ruud Sies and Hanneke van
Hintum have described it in an authentic way, and
illustrated it with captivating photographs. We felt
this story was so compelling that we would not want
the reader of this book to miss out on it.
Ruud Sies and Hanneke van Hintum develop and
produce pictorial stories with a strong documentary
character that show how people live and work.
In their work they illustrate the challenges people face
and how they try to overcome them with ingenuity
and courage. They joined forces over 25 years ago,
and as of 2017 they have been working exclusively
on “Resilience Food Stories”, an ambitious project
encompassing sustainable farming.
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ARTISAN
PRODUCTION
OF NATURALLY
DYED TEXTILES
IN THE CHILEAN
DESERT
Republic of Chile
República de Chile
Co-ordinates: Lat. 31° 28' 0" S, long. 70° 54' 0" W
Land area: 756,102 km2
Population: (2020) 18,186,770
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As Tanja Henderson uses animal-sourced fibre as a basis for her
handwoven, naturally dyed textiles, the creation process starts with
the shearing of the sheep or alpacas. A local shearer clips the animals
in small groups, bringing his own traditional hand tools.
Once the fleece has been removed, the raw wool needs to be cleaned.
For this purpose, a fine-meshed grid is used: the wool is shaken
gently, lifted and spread out so that small leaves, twigs and dirt
caught in the wool are separated and fall through the grid.
The next step consists of washing the wool in a big pan filled with
suds. Tanja uses washing-up liquid to take the oil out of the wool,
which is necessary to make it easier for the dyes to be absorbed.
Unlike sheep wool, alpaca fibre does not contain lanolin, which
means she can use a regular mild detergent to clean it. It is a timeconsuming
process, especially when using sheep wool with its high
lanolin content, because the soapy solution needs to be replenished
repeatedly. Rather than wasting the wastewater Tanja uses it to
water the trees around her house. She grows these trees, such as
eucalyptus, as suppliers of ingredients for her natural dyes.
Once Tanja is happy with the cleanliness of the wool, she dries it
by laying it out on an old towel on a drying rack in the shade.
Even in summer it may take a couple of days for it to dry completely.
The result is extremely clean wool that, as a next step, needs to be
carded. This means the fibres are all aligned in the same direction
and combed to make it easier to spin the wool into usable strands.
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Tanja does her own spinning too. And for her that
is the step where the real fun starts. Whether she
spins a thin or a thick yarn depends on the project
for which she is going to use the wool. If the thread
needs to be stronger, she can decide to first spin a
certain amount of wool into a single stranded yarn of
a specific thickness, and then spin two yarns together
to produce a more robust two-stranded twine.
Dyeing the wool can be done at two specific moments
in the process: after the clean fleece has been
carded, or later, when the wool has already been
spun into yarn. Tanja prefers the second option.
Sometimes she may also mix in some cellulose
fibre with her woven fabrics, such as cotton, jute,
and linen. She buys these materials as big cones
of unbleached and uncoloured spun yarns that are
available in varying thicknesses. The preparation
of these fibres differs from that of wool. It entails
rolling out thousands of meters of yarn, which Tanja
organises into big bunches of loose strands, so as to
make it easier for the dye to permeate.
These cellulose strands need to be cleaned too, as
some manufacturers tend to put a coating on the
yarn to protect it from dirt or water. This makes it
much harder to make the dye fix to the fibre.
Tanja uses a simple washing-up liquid to clean
the fibres. She then proceeds to prepare a bath of
dissolved caustic soda or baking powder to give
them an extra wash, followed by multiple rinses,
until the rinse water is clear.
The dyeing process of cellulose fibres is completely
different from that of protein fibre. For protein fibre,
such as wool and silk takes natural dyes quite well,
whereas cellulose fibre needs some help to dye.
There are several ways to prepare cellulose fibres
to make dyes fix to them. Tanja usually utilizes a
bean milk mordant for this purpose. It has no effect
on the colour, but makes it easier for the dye to be
absorbed by the fibres.
Due to their high protein content, the best beans
for bean milk are soy beans, but these may not
always be available. For this reason, Tanya uses
unsweetened almond milk or cow milk with added
protein as an alternative.
The clean fibres must soak in this high-protein milk
for at least 24 hours, after which they are ready to
be dyed.
Tanja only uses dyes that she has produced herself.
She also collects natural materials she finds in
nature, such as buttercups, or in her home, like
onion skins from the kitchen waste bin.
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In her garden she grows flowers like marigold, as well as
big shrubs of rosemary and her house is surrounded by
about fifty eucalyptus trees. The manure of her horses is
put to use to fertilise her garden and trees.
There are two different ways to dye wool and cellulose
fibres; one is to combine the fibre directly with all the
natural colouring ingredients and the second method
is to first make the dye and then soak the fibre in it. If
you put everything together in one pan, the petals of the
flowers added for the colour can make the wool dirty.
That is bothersome and creates extra work as the petals
need to be taken out later.
That is why Tanja prefers to make her dyes first. To do
this, she collects stuff like fallen eucalyptus leaves
or she may pick some marigold flowers. She puts
everything in a large pan of water which she heats up
over a wood fire outside.
Of course, every dye has its own recipe. Eucalyptus
leaves, for instance, need to simmer for at least one hour
for their dye to be extracted, whereas flower petals only
need hot water and no simmering at all.
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The pan with dye should stand for at least 24 hours, but generally a
waiting time of 2 to 3 days, without constant heat, gives better results.
In the summer season Tanja uses the sun as a heat source. She fills
a big pan with 4 litres of water and the sourced material and exposes
the blend to the sun. In a few days time the dye will be ready to use.
Before adding the fibre to the dye, she strains the leaves or flower petals.
And then the magic begins! The clean, prepared fibres are blended with
the dyes, and Mother Nature's colour gamut will start to reveal itself.
Having wetted the fibres, she adds them to the pan with freshly
prepared dyes, heats the contents up and lets it stand for a whole day,
or, preferably, a few days. If possible, she reheats the contents once
a day. And of course, a whole range of lovely tricks exists to obtain
multiple colours for the fibres, ‘the special effects’. After a few days
she takes the fibre out of the dyeing pan and gives it a single rinse.
Once the colouring process is finished, there are several ways to
improve the level of colour fastness of the dyes. It strongly depends on
the material that is being used for dyeing, but nonetheless, to improve
colour fastness, any type of dye will benefit from a dip in a vinegar-water
solution or an iron water dip, which will change the colour even more.
Tanja makes iron water using old horseshoes or rusty old nails that
she finds outside between building waste. She puts the nails in a glass
pot which she fills with water and vinegar. After about a week the iron
water is ready to be used.
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In order to be able to completely immerse the fibre in the iron water
Tanja dilutes the mix with as much water as needed. The fibre only
gets a short dip in the iron water, not more than a few minutes. Next, it
is properly rinsed and dried.
The dyed fibres, spun into balls of yarn, are finally ready for her
weaving projects.
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Dutch designer Tanja Henderson studied Fashion
Design at the Academy for Art and Design in
’s-Hertogenbosch and at the Gerrit Rietveld Academy
in Amsterdam. In 1987 she won first prize in a national
contest for fashion designers organised by a television
show by Linda de Mol and fashion label Fooks.
Following that, her designs were put on the market by
Fooks across the Netherlands.
Later on, she became a professional photographer
working for international museums, art institutions
and artists. Her work has been published in countless
books, magazines and newspapers.
About twenty years ago, she and her husband decided
to leave the Netherlands, with nothing more than their
cameras tucked under their arms. They spent a few
years travelling through America, living in a small tent
and an old jeep. Feeling an immense fascination for
the desert, they spent most of their time in the southwest
of the US. They went on to move to Canada,
where they lived in a remote part of British Columbia
near an indigenous community, off-grid, without a
phone or neighbours and close to grizzly bears and
pumas, the closest supermarket being a 3 hour’s drive
away (one-way).
But they found that the cold climate prevented them
from spending time in the outdoors for many months
of the year. By now they had become parents and
still feeling the appeal of the desert they moved to
yet another country with their two young children Fay
and Sid. Ten years ago, after a few short stops in the
Netherlands, they decided to settle down in a very
remote spot in the desert in the north of Chile.
The closest town is Combarbalá, situated in a very
mountainous area (Norte Chico) between the Norte
Grande with its great dry desert in the north and the
Zona Central in the south.
Here Tanja has taken up working with fabrics and
yarns again to produce unique creations. Living close
to nature she can find everything she needs for het
projects at her doorstep. She has set out to make
beautiful, natural dyes using the surrounding plants
and shrubs, even growing her own plants for the
production of botanical dyes.
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Somfy Nederland BV
Jacobus Ahrendlaan 1
Postbus 163
2130 AD Hoofddorp
Phone +31 (0)23 55 44 900
info.nl@somfy.com
www.somfy.nl
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