Solar Energy Perspectives - IEA

Solar Energy Perspectives: Buildings
Figure 4.4 Yearly primary space heating use per dwelling in selected European countries
Existing average
Typical new
Passive house
300
250
200
2
Primary energy use (kWh/m )
150
100
50
0
Austria
Belgium
Denmark
Finland
Germany
Ireland
Netherlands
Norway
United Kingdom
Source: Kaan, Strom and Boonstra, 2006; IEA, 2010a.
Key point
Newly built houses are more energy efficient, but could do much better.
Insulation technologies, very efficient windows and materials, and the art and knowledge of
conceiving very efficient buildings under a great variety of situation – cold, temperate, hot
and arid, hot and humid – exist and are widely available, though not necessarily mobilised
(see, e.g. Haggard et al., 2009). They mix up-to-date software and hardware, and breakthrough
technologies of various kinds, with traditional knowledge inherited from before cheap oil
inundated the planet.
These technologies and practices are also available for refurbishing existing buildings.
Especially when visual characteristics need to be left unchanged, refurbishing may not bring
the energy consumption of existing buildings down to the level of newly built ones, but
would still represent considerable improvement. A multi-dwelling building of Haussmann’s
era in Paris, for example, consumes about 410 kWh/m 2 /y for space heating. The most recent
regulation for new buildings sets the maximum consumption at 50 kWh/m 2 /y (with some
local variations). This includes space and water heating, cooking and specific electricity.
Insulation of the roof, the ground floor, external insulation of the back façade, the change of
all windows and doors, and the introduction of a more efficient boiler brings the space
heating consumption down to 120 kWh/m 2 /y. This is more than twice as much as a new
building, but almost 70% less than before refurbishment. The street façade looks very much
the same as before.
Full refurbishment from outside has been systematically developed in several countries in
northern Europe, with very convincing results. One project in Frankfurt reduced heating
loads to one-eighth their previous level while increasing available housing area
(Photo 4.4). The energy consumed for space heating has been reduced by 87% in this
building. High-rise buildings can also be retrofitted and considerably improved. In La
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© OECD/IEA, 2011