Energy Efficiency in Conservation Areas - Westminster City Council

Energy Efficiency in Conservation AreasContents2 Introduction3 Insulation7 Draught-proofing8 Ventilation8 Windows & doors11 Heating & hot water12 Lighting & electrical13 Water conservation14 A sustainable approach15 Materials17 Examples of good practice18 Key Advice & GlossaryBack page ContactsEnergy Efficiency in Conservation AreasKey Advice• Do not alter the external appearance of buildings in Conservation Areas without consent from the City of Westminster• Always repair where possible and replace with like for like• Insulate existing buildings as much as possible to retain heat• Upgrade windows and doors sympathetically• Draught-proof buildings to prevent unwanted air leakage and heat loss• Ensure adequately controlled ventilation is provided• Upgrade the heating system to a gas condensing boiler and install user-friendly controls• Ensure adequate daylight is provided to all habitable rooms• Install high frequency fluorescent artificial lighting, with automatic controls if appropriate• Provide energy and water efficient domestic appliances with ‘A’ ratings• Include water saving fittings and appliances• Carry out an energy advice programme to ensure effective use of energy & water efficiency features• Consider other environmental issues such as sources of materials, prevention of pollution and healthy internalenvironments• If in doubt about any issues seek assistance from The City of Westminster contacts overleaf• Listed Buildings have additional protective legislation so consult with the City of Westminster Planning Department for allproposed alterations• Ensure all works meet building control standards. Contact City of Westminster Building Control department for furtheradvice.Planning DefinitionsConservation AreasThese are defined by the Civic Amenities Act 1967 as ‘areas of specialarchitectural and historic interest, the character and appearance of which it isdesirable to preserve or enhance’. Other legislation gives protection to individuallisted buildings of specific architectural or historic interest. The City of Westminsterwill confirm if a building is located in a Conservation Area and the PlanningDepartment will provide guidance on any proposed alterations and requirementsfor Planning consent.Article 4 DirectionsThis legislation may impose additional restrictions on the treatment of facades andconservation areas, for example in Queen’s Park.Glossarybreathing a characteristic of traditional and natural materials explained further on page 15dew-point where internal moisture condenses in colder parts of a construction causing dampdraught lobby unheated space at the end of a hall with two draught-proofed doors to the outsideDPCdamp-proof course - an impermeable material that prevents the passage of moistureDPMdamp-proof membrane - an impermeable waterproof sheetEMFelectro-magnetic fields from power sourcesLSALead Sheet Association for technical manuals see www.leadsheetassociation.org.ukLSFnon-pvc electric cabling - ‘low smoke and fume’NOxnitrous oxides produced by the combustion of fossil fuels.ODPozone depletion potential of a material - chlorofrlourocarbons (CFCs) have high ODPOHLSnon-pvc electric cabling - ‘zero halogen low smoke’PVCpolyvinyl chloride - chlorine produced in manufacture can be extremely pollutingsarkingwaterproof roofing membrane which can be vapour permeableListed BuildingsSEDBUK Seasonal Efficiency of Domestic Boilers in the UK (www.sedbuk.com)This leaflet does not provide guidance for renovation or upgrading of ListedSunpipes transfer daylight down a reflective tube, usually from a roof to a lower ceilingBuildings. Works other than routine maintenance will require Listed BuildingVOCvolatile organic compound - such as formaldehyde, a suspected carcinogenConsent in addition to any other consent. For all Listed Building enquiries pleaseRSLRegistered Social Landlordcontact The City of Westminster Planning Department.1 18

Energy Efficiency in Conservation AreasEnergy Efficiency in Conservation AreasExamples of good practiceHistoric building refurbishment• Original windows restored with originaltimber shutters• Internal insulated dry-lining added to allexternal walls• Original plaster covings, architraves,skirtings and niches reproduced or reusedwhere possible• Timber floors recycled from other parts ofthe building• TRVs on all radiators run from a gascondensing boiler with an energy efficientzoned management systemIntroductiondepartment will provide guidance on alterationsthat can have varying implications for historicbuildings.Holistic ApproachEnergy efficiency is most effectively achievedwhen an integrated approach is taken to allaspects of a building’s performance. For instance,it would not be very effective to carry out insulationwithout having considered draught-proofing, asmuch of the retained heat would be lost throughuncontrolled ventilation.Therefore this leaflet covers a wide range ofenergy efficiency issues:Room-in-the-roof• Good daylighting from a rooflight onnon-principal elevation. This reduces theneed for artificial light• 300mm of cellulose insulation used incombination with vapour-permeablesarking, avoiding the need for acontinuous ventilation gap under it (seepage 5)• Natural flooring, paints and wood finishesmake this a healthy living space with lowtoxicitySecondary glazing to original windows• Original double-hung sash windowrestored• Secondary glazing divided in line withcentral mullion• Traditional timber construction and brassironmongery• Double glaze the secondary glazing toimprove efficiency• Draught-stripping is incorporated into theframe (see page 7)Energy EfficiencyThis publication is intended to provide guidanceon improving energy efficiency when renovating orupgrading existing buildings in ConservationAreas.This leaflet provides general guidance andindicates good practice.Further guidance on Conservation Areas can befound in a range of City of Westminsterpublications and Supplementary PlanningGuidance (SPG) (see www.westminster.gov.uk).The wholesale refurbishment of existing buildingsprovides an opportunity to significantly improveenergy efficiency, an opportunity perhaps thatmay not reoccur for another 30 years. Energyefficiency in buildings is of great importance as it:• reduces consumption of finite fossil fuelresources;• reduces CO2 emissions and the effects ofglobal warming;• reduces occupants’ fuel bills and improvestheir comfort.The City of Westminster supports and encouragesthe upgrading of existing building stock to improveenergy efficiency. Work to buildings inConservation Areas needs to be designed andcarried out with great care to avoid detrimentaleffects to the visual appearance, performance andcharacter of the area.There are many improvements that can beundertaken sympathetically. The Planning• insulation of floors, walls and roofs;• draught-proofing to reduce unwanted heatloss;• ventilation control by natural & mechanicalmeans;• window & door improvements for insulationand draught-proofing;• heating replacement and improved controls;• lighting & electrical energy saving.In addition, when improvements are carried outwithin an overall environmental approach, thereare a number of other significant benefits for the:• care of historic buildings;• health of occupants;• prevention of pollution.This can be achieved by:• use of traditional ‘breathing’ materialscompatible with historic buildings e.g. limeproducts• careful choice of materials that are non-toxic tohuman health e.g. organic paints and stains;• specification of products that do not causesignificant pollution in their production e.g.non-PVC;• specification of low NOx boilers, NOx beingthe main contributor to acid rain.Saving water brings further environmental benefitsand cost savings and is discussed, together withthe choice of materials on pages 13-16.172

InsulationEnergy Efficiency in Conservation AreasMaterialsEnergy Efficiency in Conservation AreasKey PrinciplesInsulating a building envelope is essential toimprove energy efficiency. Adding or increasinginsulation to floors, walls, roofs and increasing thethermal performance of windows and doors (seepages 9 & 10) can be achieved in various ways.The choice of technique will depend on theconstruction of the building, on cost limits and onplanning restrictions.When installing insulation the following keyprinciples should be followed to ensure GoodPractice, to achieve maximum energy efficiencyand cost effectiveness:• Carry out insulation as part of anintegrated energy efficiencyrefurbishment strategy;• Use as much insulation as possible -generally the benefits increase withinsulation depth;• Ensure by dew-point calculation thatinterstitial condensation will not occurwithin the construction;• Ensure that the insulation is continuousparticularly at floor, wall and roof junctionsso that thermal bridging does not occur(see page 5);• Ensure that the method of insulation doesnot cause or aggravate rot or dampnessproblems;• Use insulation with Zero Ozone DepletionPotential (ZODP) to prevent contributingto global warming.Ground Floors & BasementsGround floors are responsible for a significantamount of heat loss, up to 10%, so insulationshould be considered during refurbishment work.Planning guidance is given on page 6.Raising floors is undesirable where it disturbsoriginal features such as stone or tiling, or involvesaltering existing doors, staircases and lift access.However, some methods allow original floors andlevels to be maintained or rebuilt. Alternatively,external perimeter trench insulation can be used.Solid floor insulation• is normally cost effective if replacing afloor or existing screen, which avoidsraising floor levels• can be placed under the slab if replacinga floor, which allows a solid floor finish tobe built• can be placed above the slab, topped byboards, in place of an existing screen (seeabove)• needs technical advice if working withoriginal floors e.g. stone, earth or limeconcreteSuspended floor insulation• normally easy & worthwhile if accessavailable from below, or if renewingfloorboards (see left)• raises floor levels when added on top ofexisting timber floors with battens andnew boards• needs draughtstripping between floor,skirtings & panelling with ventilation tovoids underneath• should use open jointed boards or nettingto support insulation and avoid trappingspilt liquidsInsulationAll insulants should have zero ODP. Someinsulants, e.g. some cavity wall insulationmaterials have health hazard concerns, otherssuch as mineral fibre, use large amounts ofenergy in their production: up to 30 times that ofsheep wool. Other natural materials such as hempand flax are available and cork (see top right) isalso appropriate for use in flat roofing. Recycledcellulose insulation (see middle right) can be usedin roofs and suspended floors.PVC-free buildingsThere are significant concerns about thesustainability of PVC products in terms ofpollutants, longevity, maintainability and disposal.It is possible to produce sustainable PVC-freebuildings, with timber windows and doors, castiron rainwater goods, LSF or OHLS cabling andclay drainage.Transport of materialsAs with labour and skills, it is important to uselocally sourced materials wherever possible, toreduce the pollution arising from and the energyinvolved in the transport of bulky buildingmaterials.Repair and reuseGood design and detailing and the repair orreplacement with like for like ensures that thebuilding performance is not affected. Use recycledor reused materials wherever possible but ensurethat they are sourced from a reputable supplier.Materials & construction adviceThe AECB ‘Greener Building’ directory is a goodsource book for the environmental selection ofmaterials. ACTAC produce the ‘Green BuildingDigest: a guide to building products and theirimpact on the environment’. The BRE producevarious publications concerning the environmentalselection of materials, such as ‘The Green Guideto Specification’ and produce numerous GoodPractice Guides such as that opposite. SeeContacts on the back page for all of the above.3 16

MaterialsEnergy Efficiency in Conservation AreasInsulationEnergy Efficiency in Conservation Areas15Key PrinciplesBuildings constructed with traditional materialsoften have no DPCs, impervious membranes orfinishes that modern buildings rely on. Moisturecan be absorbed by the fabric and released againwhen better conditions prevail: this is oftenreferred to as ‘breathing’ construction. Furtherdetail is contained in SPAB Information Sheet 4‘The need for old buildings to breathe’, seeContacts on the back page.Poor choice of materials and improvements canhave a significant impact on building performance,exacerbating damp problems and acceleratingdeterioration. SPAB have a number of technicalpamphlets giving relevant advice. In addition,there is often a greater energy input in the form ofheating, ventilation and dehumidification as aresult. Damp walls do not retain heat and willincrease heat loss.It is Good Practice when renovating traditionalbuildings to introduce replacement materials thatare similarly ‘breathable’. When extending inmodern materials and carrying out refurbishmentworks at the same time, two separatespecifications are needed.Materials can have a significant impact on theenvironment and the health of occupants. Beforechoosing a material, please consider:• the source of its original raw materials• manufacturing processes• transport of resources and products• the impact on a building and its occupants• the issues surrounding removal anddisposalA number of subjects are discussed below inrelation to the above issues.Lime mortarThe porosity of lime and earth based mortar andrenders permits evaporation of moisture fromwithin the wall. The application of cement pointingand renders on traditional walls is largely nonporousand may lead to damp, rot anddeterioration. Lime and earth based mortars arewidely available, use less energy in theirproduction and can easily be removed frombuildings allowing recycling and reuse.TimberAll timber used in building and finishing should besustainably sourced. The Forest StewardshipCouncil (FSC) runs a credible certification schemeto label such timber (see Contacts). Leadingcampaigners advise that other certificationschemes should be approached with caution.They should have objective and measurablestandards, demonstrate a credible chain ofcustody and have a system for independentassessment or audit.Timber products that use glues e.g. particleboards can contain VOCs which should beavoided.Timber treatmentIt is usually advisable to seek professional advicefrom a suitably experienced architect or surveyorbefore employing the services of a commercialcompany. In many cases, prevention by gooddesign and maintenance is better than a cure. Theunnecessary destruction of fabric and use ofchemicals is often unjustified.A number of publications are available, such as‘Timber Decay in Buildings: the conservationapproach to treatment’ by Brian Ridout, EnglishHeritage & Historic Scotland in association with E& F Spon (ISBN 0 419188 20 7). English Natureshould be contacted where any proposed workscould put bats or wildlife at risk.Paints & stainsLimewash was widely used to decorate buildingsinternally and externally. This is a porous materialand is still available. Modern petrochemical paintsform a barrier to moisture and exacerbateblistering, condensation and mould problems.Organic-based paints and stains are porous andare much less polluting or toxic in theirmanufacture, application and to the occupants of abuilding.Further information on the health hazards of paintscan be obtained from the London Hazards Centre(www.lhc.org.uk). Materials such as oak can beconsidered, which do not require paints or stains.Figure 1New concrete ground slab with insulation beneath(replacement floor to existing levels)Figure 2Concrete ground slab with insulation and boardsover (replacement screen to existing levels)Key to Figures 1- 41 Insulation with ZODP (flooring grade in Figs1&2)2 Perimeter insulation to new slab and screen3 DPM laid to overlap DPC in wall4 New timber boards can be supported onbattens5 Draught-sealing around internal wall insulationFigure 3Suspended timber floor with access from below(existing boards and levels)Figure 4Suspended timber floor with access from above(replacement boards to existing levels)6 Support netting fixed to underside of existingjoists7 Perimeter insulation to be used whereverpossible8 Draught-sealing between skirting and floorboards(particularly if no wall insulation as item 5)9 Support netting laid over joists from above4

Energy Efficiency in Conservation AreasEnergy Efficiency in Conservation AreasInsulationRoof InsulationRoofs can be easily and cost effectively insulated.Where possible, use vapour permeable sarking toavoid the need for visible external vents. Whereadditional ventilation is required, ensure thatexternal vents at eaves, ridges and down the pitchare sympathetically designed and specified.Loft insulation• should completely cover all ceilings belowand overlap any wall insulation• must allow good ventilation to the loftspace without blocking eaves or soffitvents• results in colder loft spaces so water tanks& pipes should be insulated or removed toavoid freezingRoom-in-the-roof insulation• can be applied in-line with the sloping rooffrom inside behind a vapour checkplasterboard• usually needs a continuous ventilationgap above it• can be added above existing timbers fromoutside• should be continuous with insulation in theceiling above and in the walls belowFlat roof insulation• can be applied to existing roofsparticularly when renewing a roof deckand finish• needs a continuous ventilation gap to bemaintained above it when laid betweenjoists• can be added on top of an existing deck(without ventilating below it) orunderneath existing ceilings• refer to LSA manuals for lead roofs (seeglossary)Key: Figure 51 Continuous line of insulation with ZODP2 Minimum 50mm ventilation gap maintainedunder existing roof or vapour impermeablesarking3 Equivalent of 25mm continuous eavesventilation gap, with insect mesh4 Wall and ceiling finish usually with a vapourcheck membrane behindAvoiding Thermal BridgingThermal bridging occurs where insulation is notcontinuous or is bridged by materials such asmasonry or timber with a higher rate ofconductivity. Then heat loss increases andcondensation can be a problem. It is not aplanning issue and it should be carefullyconsidered when insulating.Care is needed particularly with internal insulation:around openings, at the junction of wall and roofinsulation, and where intermediate floors andpartitions meet external walls. Thermal bridgingcan be avoided by:• carrying insulation around all window and doorreveals up to the frames• ensuring roof insulation reaches the top ofexternal walls without blocking ventilation• applying a metre of insulated dry lining to bothsides of internal walls as they join external walls• insulating in the ceiling cavity below a parapetgutter before the flat roof insulation can begin• insulating in ceiling cavities under intermediatefloors at the break in the wall insulation• ensuring rooflights are detailed to avoid thermalbridging, including conservation productsFigure 5Typical room-in-the-roof detailing showing in-lineroof insulation with loft and internal wall insulationA sustainable approachSustainability issuesAll buildings, in their construction and in their usehave a significant impact on the environment.Demographic trends, projected to 2016, show thenumber of households per head of populationdoubling from 1861. The current and futurechallenge in the maintenance and construction ofall housing is to balance or reconcile its impactswith the benefits gained.In addition to energy efficiency and waterconservation, the main sustainability issues toconsider when refurbishing traditional buildingsinclude:Use of local labour & skills• to support local economies and theviability of local businesses• to encourage traditional building skills andcrafts using local materials• to reduce reliance on transport leading toa reduction in energy use and pollutionPreventing pollution• by employing energy efficiency measures• by using products that do not containCFC’s/HCFC’s, VOC’s, heavy metals orPVC• by avoiding equipment that contributes toacid rain, produces NOx or airborneparticulates• includes avoiding products fromcompanies responsible for pollution in thedeveloping worldBetter buildings for health• by designing correct thermal & ventilationlevels• by using non-toxic materials &components, such as organic-basedpaints and stains• by avoiding VOCs - e.g. urea -formaldehyde foam insulation which hashealth hazard concerns• by considering the design of domesticelectrical systems to avoid ElectroMagnetic Fields (EMFs)• includes considering the health of buildersChoice of materialsThe environmental selection and use ofconstruction and finishing materials must beappropriate for traditional buildings. It is a largesubject and is discussed on the next page.Energy AdviceWhilst a building can be designed to be energyefficient, it is how the building is used that willultimately determine how efficient a building willbe. It is good practice to complement the energyefficiency improvements with an energy adviceprogramme. This will enable occupants to:• understand their heating & controlsystems• reduce their fuel bills & budget for fuel• alter their behaviour to save energyRSLs are in a unique position to undertake anenergy advice programme, containing forexample:• simple system-specific energy advicehandbooks• home visits by a qualified energy adviser• energy advice surgeries for problemsolving• energy advice talks at residents’associations• tips and advice incorporated in RSLnewsletters• a show house used as a demonstratorEnergy advice to occupants should include:• how to use heating controls &programmers• recommended temperature settings• controlling condensation• efficient use of appliances & low energylights• grants for energy efficiency improvementsContractors should also be educated to giveenergy advice that is consistent with the aboveprogramme. Contact the Energy Efficiency AdviceCentre for more information (See Contacts)5 14

Energy Efficiency in Conservation AreasEnergy Efficiency in Conservation Areas13Water conservationMains water useOver half the 33 billion litres of water extractedeach year in the UK is used by the domesticsector. It is important to address waterconsumption in homes due to rising environmentalconcerns. Water costs can be more than thecombined cost of gas and electricity in a wellinsulated house.Water saving appliances can be fitted into existingbuildings to make 24% to 47% savings without anyimpact on the external appearance. As withenergy, water efficiency is determined by theactivity and habits of occupants. Further advicecan be sought from the Environment Agency (seecontents).Rainwater useRainwater collection can be considered for WCflushing, cleaning and watering to save up to 50%of household mains water consumption.Rainwater package systems are now readilyavailable which comprise of a centrifugal filter,storage tank, pump and controls. Tanks can belocated underground or in a basement. Rainwatercan be pumped to WCs directly or to a holdingtank inside.Manufacturer’s instructions and water authorityregulations should be followed at all times.A specialist can be consulted for further advice.Rainwater system components - a downpipe filter(left) can be fitted easily into an existing drainsystem & an underground filter (right) is usuallypart of a new system: both filter out particles &debrisWater conservation adviceThe Environment Agency’s factsheets entitled‘Conserving water in buildings’ providescomprehensive guidance on all aspects of wateruse and appliances: see Contacts on the backpage.WCsSome WCs can use 9 litres of water a flush. Newerlow flush WCs have 2 to 4 litre flushes. Waterlessor vacuum toilets may only be appropriate inparticular circumstances. It is sometimes possibleto reduce the flush of existing WCs with adisplacement or delayed fill device, though not ifthe WC then needs to be flushed more than once.Baths, showersand tapsTapered and insulatedbaths save water andenergy.Showers should be fittedwith thermostatic mixervalves and low water useheads.Spray taps save up to 80%of the water and energyused by standard pillartaps and aerators reducesplashing and give theillusion of greaterwater flow.InsulationWall InsulationExisting walls can be insulated in a number ofways. All walls should be fully surveyed to currentBritish Standards and deterioration corrected priorto insulating. Traditional walls have a greaterability to ‘breathe’ (explained on page 15), so theimpact of any insulation on the overallperformance of the building should be fullyassessed at design stage. Planning guidance isgiven below.Internal wall insulation• is recommended for solid walls using aninsulated dry lining system (usually withvapour control) which does not affectexternal facades• is easy to install and can accommodatenew service ducts and conduits (see right)• avoids thermal bridging (see page 5) andinterstitial condensation when correctlydetailed• can cause additional problems if any timberused is not isolated from external walls usinga DPC• improves draught-proofing of a buildingwhen sealed around its edges, see alsopage 7• should be carefully detailed to avoiddamaging internal features e.g. aroundwindows & doorsCavity fill insulation• is recommended where masonry cavities exist• should not use materials that are a healthhazard• can damage facades during injection unlesscare is taken when positioning and drillingholes• should be installed by a manufacturers’approved contractors using a testedand certified product (e.g.with a BritishBoard of AgrÈment Certificate)External wall insulation (EWI)• is not preferred if existing externalfeatures and facades need to be retained• can be used to reproduce lost originalfeatures where traditional materialscannot be used• provides the highest insulation levels androom sizes are not reduced• easily avoids thermal bridging andprovides protection to existing walls• makes use of thermal mass in existingwalls• should be undertaken by a manufacturer’sapproved contractor using a testedproduct with third party certification (suchas BBA)Watch points• Prior to insulating, ensure that existingstructural, damp and rot problems havebeen eliminated• Never block existing ventilation holesunless an adequate ventilation method isto be provided• Always ensure that any timber used isisolated from external construction by aDPC• Always use non-PVC conduit, particularlynext to polystyrene insulation which canreact with itPlanning GuidanceGuidance should always be sought for majorrefurbishment works. Where there is no legislativecontrol, good practice in the care of historicbuildings should still apply. SPAB publishes suchtechnical guidance, see Contacts on the backpage.The following general guidance is given:• Floor and basement insulation isacceptable by following good practice forhistoric buildings• Dampness and rot problems should notbe treated unnecessarily with chemicals,see page 15• Internal insulated dry lining is acceptablewhere internal features are not historicallyimportant• Cavity wall insulation is acceptableprovided care is taken making injectionholes• External wall insulation should only beconsidered in consultation with thePlanning Department• Loft insulation combined with vapourpermeable sarking eliminates the need forvisible roof vents• Flat roof insulation can add thickness thatshould be kept below original upstandsand parapets6

Energy Efficiency in Conservation AreasEnergy Efficiency in Conservation AreasDraught-proofingKey PrinciplesUnwanted air enters and leaves buildings in manyplaces such as through suspended timber floorsand around service pipes, see Figure 6.Draught-proofing prevents significant heat loss,increases comfort levels and reduces runningcosts.Old buildings rely on uncontrolled ventilation todeal with the expulsion of undesirable gases andwater vapour and so draught-proofing must becarefully thought through in conjunction with themethods of ventilation to be used.It is good practice to ensure that a new buildingachieves a measured amount of air tightness,done with a fan pressurisation test. This can beuseful during refurbishment work to identifysignificant air leaks for sealing. For furtherinformation on testing contact the BRE, seeContacts on the back page.Draught-proofing is one of the most simple andcost effective energy efficient measures forexisting buildings and is rarely a planning issuewhere it does not affect the external appearance ofa building.Figure 6Diagram showing uncontrolled air infiltration into abuilding which are also passages for heat lossWatch points• Do not block up air bricks and permanentventilation to floors, roofs and sealedchimneys• Do not block up vents for heatingcombustion• Omit some draught-stripping if there areno trickle vents particularly in kitchens andbathrooms to help prevent condensationproblems• Use vapour permeable materials to allowthe building to ‘breathe’ (see page 15)Effective draught-proofing• Overhaul windows and doors includingdraught-stripping and secondary glazing(see page 9)• Point around window and door framesinternally with sealant, externally with limemortar• Draught-strip and insulate the loft hatch• Seal around internal dry lining with acontinuous ribbon of plaster adhesive or apre-compressed expanding foam strippinned around the edges• Seal off unused chimneys (includeventilation)• Seal around services such as pipes andducts passing thorough floors, walls androofs• Seal existing skirtings to floors (see page 3)• Use sheet floor finishes or underlaybeneath carpets and draught-excludersunder doors• Replan entrances to incorporate draughtlobbiesLighting & ElectricalKey PrinciplesArtificial lighting and domestic electricalappliances account for a large proportion ofenergy use in buildings. It is important to consider:• daylight provision that cuts down energyuse by artificial lighting, even in existingbuildings;• position, control and specification ofenergy efficient artificial lighting;• choice of energy efficient electricalappliances.Automatic artificial lighting controlsPresence detectors and daylight level detectorsDaylight DesignWhen replanning or refurbishing buildings, ensureadequate daylight is provided to all habitablerooms. Seek guidance from The City ofWestminster Planning Department for any externalalterations to a building in a Conservation AreaThe effect of daylight can be improved, giving apleasant internal environment and reducing theneed for daytime artificial lighting.• Use light coloured floor, wall & ceilingfinishes that reflect light into and aroundrooms.• Borrow light from other rooms andcorridors with sensitively designedinternal glazing in doors or partitions (seeWatch points).• Install rooflights on non-principalelevations with approval from thePlanning Department.Consider ‘Conservation’ rooflights fitted‘in-line’ or flush with the roof finish (seeWatch points).• Install ‘Sunpipes’ from roofs on non -principal elevations. Ensure these areacceptable to the Planning Department.Artificial LightingEnergy efficient artificial lighting relies on followingthese guidelines:• Design and position lighting that isappropriate for the use of the room;• Concentrate lighting at task areas ratherthan trying to achieve an overall light levelin the whole room;• Zone lighting so that badly day lit roomareas can be lit separately from the wholeroom;• ‘High Frequency’ fluorescent light fittingsreduce energy use, maintenance andelectricity costs;• Specify energy saving controls - considerusing PIR (passive infra-red) presencesensors with automatic ‘off’ switches forshared areas;• Install fittings with built-in ballasts that willonly accept compact fluorescent lamps.Electrical AppliancesEnergy efficient and environmental specification ofelectrical appliances should include:• White Goods with ‘A’ ratings;• CFC/HCFC free refrigerants;• larder fridges (with no freezercompartment);• separate freezers;• ‘load intelligent’ washing machines &dishwashers;• gas for cooking;• combination microwave ovens.If appliances are not provided in the refurbishmentworks, then provide occupants with sufficientinformation on the above to make their ownchoices.Watch points• Only use double glazed ‘Conservation’rooflights with thermally broken frames &integral draught-stripping and preventthermal bridging at reveals.• Check with Building Control regarding fireprotection of internal glazing for borrowedlight.• Do not use glazing if it damages originalfeatures.• Make sure that energy efficient externallighting is also specified.• Dispose carefully of all old electricalappliances - they may be able to berecycled or re-conditioned.7 12

Energy Efficiency in Conservation AreasEnergy Efficiency in Conservation Areas11Heating & Hot waterKey PrinciplesUpgrading the heating system of a building can bethe most effective energy efficiency measure thatcan be undertaken.Efficient and well controlled equipment must beused. Systems should be designed to avoid visibleexternal services and minimise internal impact.The many benefits include:• reducing fuel bills;• reducing CO2 emissions;• reducing NOx emissions;• improving occupant comfort and usercontrol.These benefits increase with the number ofassociated energy efficiency measuresundertaken e.g. insulation and/or draught-proofing.It is important that heating is considered in anintegrated approach to refurbishment and the fullimpact on the building’s performance, e.g. on itsability to deal with damp and moisture, isconsidered.2-channel programmersCentral heating systems should have easy toaccess, user-friendly controls with separateprogrammable on/off and boost controls forheating and hot water. Energy advice to occupants(see page 14) should include how best to operatethem.Boilers and ControlsBy far the most common solution to providingdomestic heating and hot water is gas centralheating. Specification of the system should followEnergy Efficiency Best Practice guidelines:• Use a condensing boiler with an A or Brating listed in SEDBUK databasewww.sedbuk.com;• Use a fast recovery hot water cylinder or acondensing combination boiler;• Specify a 2-channel programmer, a roomthermostat, cylinder thermostat and TRVson all radiators except those adjacent to aroom thermostat.These additional guidelines are also important:• Use condensing boilers that produce thelowest levels of NOx emissions: below 70mg/kWh;• Lag all primary pipe work runs and hotwater storage with at least 50mm ofZODP insulation;• Use softeners to prevent build-up oflimescale and ensure efficient running ofequipment;• Provide full operating manuals and fulluser instruction on the controls (see page14);• Keep pipe runs to a minimum to avoidheat loss, otherwise consider direct pointof use boilers;• Make use of wire-less technology thatreduces the need for wiring throughhistoric interiors;• Combination boilers avoid the need forhot and cold water tanks and associatedplumbing;• Run condensate drains internally;• Use a registered insurance-backed Corgigas system installer (or equivalent forother fuels).Planning GuidanceThis guidance is aimed at the protection of thefabric and external character of a building. Flues,terminals and obtrusions need to be carefullyhandled outside and inside buildings inConservation Areas.• Any obtrusions on the facades of abuilding may require Planning consent• Consider vertical flues that can run insideto the roof: condensing boilers can have6 -11m flues.• Take great care with the detail design ofinternal service runs to not damageoriginal features.VentilationKey PrinciplesControlled ventilation is essential for energyefficiency and to maintain air quality for a healthybuilding, which should be designed to:• avoid excessive heat loss and highenergy bills• prevent build up of condensation anddampness leading to mould growth• help deal with solar gain and build-up ofheatA ventilation strategy is vitally important whenundertaking draught-proofing of an existingbuilding (see opposite). Passive ventilation can beintroduced sympathetically into historic buildings,otherwise low-energy mechanical ventilationshould be optically controlled with timers andhumidistats.Planning Guidance• All ducts should be accommodatedinternally• External vents in walls or roofs should bedesigned and located to have least visualimpact. Proprietary products are notalways appropriateFigure 7Diagram showing ventilation of a house usingwindow ventilation and passive stacksWindow ventilation• should be available in all rooms withproperly maintained opening windows toallow user control• should include background ventilation viatrickle vents in the frames to help combatcondensation• can sympathetically incorporate tricklevents if restoring traditional windows, asbelowFigure 8Concealedcill trickle ventPassive stack ventilation• is a zero or low energy controllablealternative to mechanical ventilation withminimum maintenance• requires near vertical smoothly lined ductsto run from kitchens and bathrooms to theroof• extracts moisture by stack effect (themovement of air due to temperaturedifference) & wind effect• provides a continuous level of backgroundventilation when used with trickle vents inwindowsLocal extract ventilation• requires care when positioning externalwall and roof extract terminals so as not tobe unsightly• should use low wattage mechanical fansto reduce energy use and running costs• must be positioned close to the source ofpollution or moisture and away fromincoming fresh airMechanical ventilation & heat recovery• can have a marginal effect on overallenergy consumption unless it is a very lowenergy system• can have payback periods in excess of 40years• is most beneficial for asthma or allergysufferers to improve indoor air quality8

Energy Efficiency in Conservation AreasEnergy Efficiency in Conservation AreasWindows & DoorsKey PrinciplesWindows, rooflights and doors are very importantfeatures of buildings in Conservation Areas. It isessential to follow the Planning Guidanceopposite.The design and production of modern windowsand doors has greatly improved their energyefficiency. This has resulted in a change ofcharacter and detail not always appropriate forhistoric buildings - frames are thicker toincorporate multiple layers of glass and proprietaryseals. There are some energy efficiency measuresthat are appropriate to use for historical windows,but these key principles apply:• Increase the number of barriers to theoutside using secondary glazing, shuttersor heavy curtains• Decrease the amount of air infiltration andconsequent heat loss around and throughframes• Carry out thorough maintenance toensure casements continue to fit tightly &sashes shut firmlyAcceptable window refurbishmentOriginal windows are restored and new copiesadded at roof level. Any secondary glazing shouldline up with the restored window membersFigure 9Secondary double glazing to an original sashwindow showing draught-proofing measuresWindows & DoorsInappropriate modern windows degrade theVictorian character of this Queen’s Park cottage.Planning GuidanceEach window, rooflight, door and associatedhistorical features should be consideredindividually and guidance on their refurbishmentshould be sought from The City of WestminsterPlanning Department.When upgrading their energy efficiency, thefollowing guidelines should be followed:• It is a breach of Planning Regulations tomake external alterations withoutPlanning Consent;• Retain and repair all original externalfeatures;• Replace with facsimiles of the originaldesign where the originals are missing orbeyond repair;• Use original materials - do not use PVC-uor other non-traditional materials;• Double glazed replacement windows areusually not desirable in ConservationAreas;• Secondary glazing divisions should lineup with the existing window design.Improving Energy EfficiencyTraditional windows and doors are usually singleglazed without draught-proofing, with a U-Value ofaround 5.0 W/m2K, while modern designs achieve1.5 W/m2K and above. Modern triple glazedreplacement windows may be acceptable on rearfacades. The following measures retain thehistorical integrity of windows and doors:• Careful sympathetic draught-proofingmeasures• Refurbishment of existing shutters or theintroduction of new insulated anddraught-proofed shutters• Fitting heavy fabric curtains with a thermallining• Installing high performance secondaryglazing• Thorough and regular maintenanceThere are associated benefits with the above:• Reduced draughts & improved thermalcomfort• Reduced condensation on windows• Reduced ingress of noise, dust andsmoke• Improved fitting and operation of sashesKey1 External lime mortar pointing and internalsealant2 Proprietary draught-stripping system to sashes3 Secondary double glazing with integraldraught-stripping and a traditional timber frameAction Benefits Watch pointsDraught-proofingof original doorsand windowsInternal insulatingshutterInternal heavycurtains withthermal liningsInternal secondaryglazingLow cost & simple to undertakeLeast intrusive if done sympatheticallyWide range of products for all windowsSuccess and longevity is ensured byusing quality workmanship & materialsLow cost if refurbish existing shuttersAdd draught-stripping to the framesCan have other acoustic benefitsEasily provided for relatively smalladditional costDoes not affect original buildingMost effective energy efficiency solution,can reduce U-values to 1.5 W/m2KDouble/triple gas-filled glazed units withlow-E coatings can be used with integraldraught-stripping in the framesNeeds careful specification and installationEnsure draught-stripping is complete and provideadequate controlled ventilation to the room (seepage 3)Different situations need different solutionsHigh cost if newCareful detailing & craftsmanship requiredDo not damage existing internal features wheninstalling new shuttersNot very thermally effective due to limiteddraught-proofingDiscomfort from draughts may remainHigh cost itemMust ensure external appearance is notaltered - see Planning Guidance aboveNot appropriate for some complex openingsCareful detailing is always required9 10