Building And Remodeling To Save Energy

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Title:
Building And Remodeling To Save Energy
Physical Description:
Fact sheet
Creator:
Cook, Gary D.
Publisher:
University of Florida Cooperative Extension Service, Institute of Food and Agriculture Sciences, EDIS
Place of Publication:
Gainesville, Fla.
Publication Date:

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Collected for University of Florida's Institutional Repository by the UFIR Self-Submittal tool. Submitted by Melanie Mercer.
Publication Status:
Published
General Note:
"Publication date: November 1992."
General Note:
"EES-35"

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University of Florida Institutional Repository
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University of Florida
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All rights reserved by the submitter.
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IR00004846:00001


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FactSheetEES-35 November1992 BuildingandRemodelingtoSaveEnergy1 GaryD.Cook2Homeenergyconservationmeasuresthatsave moneyonutilitybillsareparticularlyimportantin Florida.Utilitycostsarepredictedtogrowmuch fasterthantheinflationratebecauseourincreasing populationiswideningthedemandfornewelectric andgashookups. Someconservationmeasuresareassimpleas turningofflights,keepingdoorsshut,andturning thermostatsupinsummeranddowninwinter. Energyusecanbereducedbyselectingfromavariety ofdesign,construction,andremodelingstrategies. Someofthesemayrequireanadditionalinvestment ofmoney,butnotalways.Agoodinvestmentwill providealargeutilitysavingsatlowinitialcost. Homeownersshouldalsoconsiderappearance, potentialforresale,andcomfortorsecuritywhen contemplatingcost-savingmeasures.Forexample, insulatedordoublepanedwindowsgivearelatively poorpaybackinenergysavingscomparedto investment.Theymay,however,reduceoutsidenoise levels.Exteriorshutterssaveenergyandmayalso providesecurityandcomfort.Properlydesigned fireplacesprovideheatandaestheticaccenttoa home. Figure1.Landscapingcansaveenergyrequiredto coolorheatahome.HEATTRANSFERAnunderstandingofhowheatistransferredinto oroutofahomewillaidyouinselectingenergy conservationmeasures.Briefly,heatistransferredby conduction,convection,orradiation.Heatis transferredbyconductionthroughdirectphysical contactofawarmersurfacewithacoldersurface (heattravelsfromafryingpantoitshandle). 1.ThisdocumentisFactSheetEES-35,aseriesoftheFloridaEnergyExtensionService,FloridaCooperativeExtensionService,InstituteofFood andAgriculturalSciences,UniversityofFlorida.Publicationdate:November1992. 2.GaryD.Cook,EnergyExtensionServiceSpecialist,SchoolofBuildingConstruction,CooperativeExtensionService,InstituteofFoodand AgriculturalSciences,UniversityofFlorida,GainesvilleFL32611. TheFloridaEnergyExtensionServicereceivesfundingfromtheFloridaEnergyOffice,DepartmentofCommunityAffairsandisoperated bytheUniversityofFlorida'sInstituteofFoodandAgriculturalSciencesthroughtheCooperativeExtensionService.Theinformation containedhereinistheproductoftheFloridaEnergyExtensionServiceanddoesnotnecessarilyreflecttheviewsoftheFloridaEnergyOffice. TheInstituteofFoodandAgriculturalSciencesisanequalopportunity/affirmativeactionemployerauthorizedtoprovideresearch,educational informationandotherservicesonlytoindividualsandinstitutionsthatfunctionwithoutregardtorace,color,sex,age,handicap,ornational origin.Forinformationonobtainingotherextensionpublications,contactyourcountyCooperativeExtensionServiceoffice. FloridaCooperativeExtensionService/InstituteofFoodandAgriculturalSciences/UniversityofFlorida/ChristineTaylorStephens,Dean

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BuildingandRemodelingtoSaveEnergy Page2Conductiveheattransfercanbereducedbyinsulation Figure2.Anenergyinefficienthome. suchasbatts,fill,orfoamplastics. Transferencebyconvectionisacombinationof massandheattransfer(acandleheatsuptheair aboveit;thewarmairrisesandisreplacedbycolder air).Convectiveheatlossisreducedbymakingthe hometightthroughsealing,weatherstripping, caulking,andproperdesign. Radiationheattransferoccursbyelectromagnetic waveforcewhenonesurfaceishotterthananother. Thesesurfacesdonothavetobeincontact.Thisis theonlyheatthatcantravelthroughavacuum(the sun'sheatisentirelyfromradiation).Thebestwayto controlradiationisbyshadingandusingreflective radiantbarriers. Ourfeelingsofwarmthorcoldnessareinfluenced bythesurfacetemperatureofobjectsaroundus,air circulation,andhumidity.Wefeelcoldwhenobjects aroundusarecold,whenairisblowingaroundus (windchillfactor),andwhenthehumidityislow.We feelhotwhensurfacesaroundusarehot,whenair circulationispoor,andwhenhumidityishigh. Rememberingthewaysheatistransferredandwith considerationforcomfortandcostefficiency, homeownerscanlookatseveralenergy-savingoptions whenbuyingorremodeling.HOMEDESIGNThegeometricdesignofahousewillinfluence bothitscostanditsenergyefficiency.Ahousewith alength-to-widthratioofone-to-one(square)will have25percentlessmaterialinitsexteriorwallsthan Figure3.Anenergyefficienthome. acomparablehousehavingafour-to-oneratiolong rectangle).Reducingwallareausuallytranslatesinto reducedenergylosses.SeeFigures2and3. Althoughapleasantfeature,anopencourtyard increasessurfaceareaand,therefore,energylosses. Somebuildersbelievethatahousewithalengthto-widthratioof1.7:1isbestforthehot,humid climateofFlorida.Thisistrueonlyifthelongside facesnorthorsouthandifthehousehasadequate overhangs.Placingthegarage,workshops,porches, bathrooms,andclosetsontheeastandwestsideof thehousewillreduceradiationgainfromthesunby actingasabuffer. Becauseofourabundantsunshine,landscapingis oneofthemostattractiveenergyconservation measures.Treesontheeastandwestsidesofa homeprovideshadeandprotectionfromthesun.In addition,shrubberycanbeplacedtocapturethe naturalbreezes.Countyextensionagentscanprovide detailsonwhattypesoftreesorshrubberytoplant. Inatypicalhome,moreenergyislostthrough glassdoorsorwindowsthanthroughanyother constructionelement.Thisisparticularlytruein Florida.Thedirectioninwhichwindowsfacewill greatlyinfluencetheenergyrequiredforheatingand cooling.Properlydesignedoverhangs(about21/2 feet)canalmostentirelyeliminatedirectsolar radiationthroughsouth-facingglassinthesummer, butwillallowheattoenterinthewinter.West-facing andeast-facingwindowsandglassdoorsshouldbe kepttoaminimum.Thisisbecausethesun'sdirect radiationisdifficulttocontrolinthesummerand,

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BuildingandRemodelingtoSaveEnergy Page3therefore,overhangsmustbeexcessivelylong(and expensive)tobeeffective. Replacingwindowswiththermaldoublepaned typesisnotacost-effectiveoptionasmentioned before,butshadingoftheeastandwestwindowswill saveenergy.Useofcurtainsisnotasattractivean optionasexteriorshading.Thebestexteriorshading devicesarelandscaping,BahamaorBermuda shutters,solarscreen,overhangs,andawnings. Window film isanoptionparticularlyifplacedonthe outsideoftheglass.Iffilmisplacedontheinside, theglasstendstoheatup. Particularattentionshouldbegiventothe shadingcoefficientofthedeviceorscreenbeing considered.Ashadingcoefficientof0.5meansthat 50percentofthesun'sradiantenergyisfiltered. Someshadingdeviceshaveshadingcoefficientsaslow as0.13;theywilleffectivelyscreenout87percentof thesun'sradiantenergy. Onahotsummerday,moreenergywillcome throughjustonesquarefootofclearglassthan throughanentireinsulatedwall.Over90percentof thatenergyisintheformofradiantenergy.Thermal panedwindowshaveverylittleeffectonradiant energyunlesstheglassistintedorsomehowshaded. Windowsshouldalsobeorientedhorizontallyto providemaximumviewingbenefit.Horizontal, comparedtovertical,windowsprovidemore ventilationbecauseofthewaythepressurebuildsup onthesideofthebuilding.Windowsshouldbe designedtoopen,sothatonmoderatedaysthehome isopenedtobreezes. Addinginsulationcanbecosteffective,especially intheattic.Iftheattichasbattinsulation,thereis noproblemwithblowinginsulationsuchascellulose ontopofit.Itdoesn'tmatteriftheinsulationisof thesametype:fiberglassmaybeaddedtocelluloseor viceversa.Itissuggestedthatbattinsulationnotbe placedoverblo'Aminsulation,butthereverse operationispossible. Accordingtorecentresearch,oneofthebest energysavingoptionsinanatticistheadditionofa radiantheatbarrier.Foil-backedpaperisplacedon topoftheexistinginsulationorstapledtotherafters ortrussessothatthereisanairspaceeitheraboveit orbelowthereflectivesurface.Atleasta1/4-inchair spacenexttothereflectivesurfaceprovidesthe barriereffect.Thereflectivesidedoesnothaveto facetheheatsourcetobefullyeffective.Thisisa Figure4.TypesofInsulation. relativelylowcostmeasurewithabigenergypayback. Properinstallationisveryimportanttoachieve theR-valueorlevelofinsulationyouarepayingfor. Forexample,iftherearegapsintheinsulationnext tothestudswherethewiresgofromthewalltothe atticoutlet,insulationperformanceislower. Compressingtheinsulationwillalsodegradeits performance.A3percentgapintheinsulationwill degradeperformanceby20percent.Compression willdegradeperformanceinanearlyone-to-oneratio. Ifinsulationiscompressedbyhalf,theperformance isreducedbyalittlemorethanhalf. Typically,20percentofenergythatislostthrough infiltrationenterstheatticbywaysofgapsin insulationnearwiresinthewallandthrough electricaloutletswitchcovers.Placingfoaminserts overswitchcoversisaneffectivewaytostopthisair infiltration.Foamoutletcoversshouldbeaddedto outletsonboththeinsideandoutsidewallstobefully effective.Childproofcoversshouldbeinsertedover theoutletsnotusedandcanbepurchasedatmany discountstoresandbuildingsupplyhouses.AIRCONDITIONERSANDFURNACESReplacementofanairconditionermorethan10 or12yearsoldorofverylowefficiencymaybean option,especiallywithmanyutilitycompaniesoffering cashrebatesforinstallationofmoreefficientmodels.

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BuildingandRemodelingtoSaveEnergy Page4Thecombinationofrebateandtheenergysavings Figure5.SolarWaterHeatingcanbeanEnergyEfficientConstructionOption. maymorethanoffsetthepricetag.Anairconditioningcontractorcanexplainefficienciesofnew models.Theseasonalenergyefficiencyratioisan indicatorofitsefficiency.Thehigherthenumberthe better.However,ifthemodelhasanefficiencyratio ofover10,havetheairconditioningcontractorverify thattheirmodelwillbeabletoremoveenoughinside moisturetokeephumiditylevelstolerable. Replacementofoilandelectricheatingsystems withanefficientheatpumpornaturalgasfurnace mightbeaverycost-effectivedecision.Byusing eitheranefficientheatpumpornaturalgassystem, heatingcostsmaybereducedtoone-thirdthecostof heatingwithelectricstripheat.Aheatpumpis designedtocoolinthesummerandprovideheatin thewinter.Theheatingsideefficiencyisratedby coefficientofperformance(COP).Thehigherthe COPthemoreefficienttheheatingside.Aunitwith aCOPof2.5willprovide21/2timesmoreheatasan electricstripheaterusingthesameenergy.Before replacinganelectricfurnacewitheithergasoran electricheatpump,askyourutilitycompanyifit offersrebateorincentiveprograms.SAVINGSWITHFANSFanscansaveenergydollars.Aceilingfancan beusedwithorwithoutairconditioning.Withthe windowsopenduringmoderateoutsidetemperatures, afancanbeusedwithoutairconditioningtoprovide awindchilleffect.Withairmovement,temperatures ashighas84or85degreesaretolerablewithoutair conditioning.Whenusedwiththeairconditioner,the thermostatmaybesetbetween82and85degreesto providethesamecomfortasathermostatsetat78 degreeswithnofan.Manyceilingfanscanbe reversedinthewinterheatingseasontocirculate warmairthatcollectsneartheceiling. Useofawholehousefanisanotheroption. Thesecansuckingreatquantitiesofairfromthe outside,pushingitthroughtheatticandproviding twobenefits:awindchilleffectwhilebringingin moderateoutsideairandsignificantatticcooling.A wholehousefancanprovideanadditionalbenefitby removingindoorpollutants(cigarettesmokeand cookingodors)veryrapidly.Wholehousefansshould notbeusedduringperiodsofhighhumidityorwhen airbornepollutants(dust,smoke,orpollen)arehigh. Atticfansandturbineventsdesignedtocoolonlythe attichavenotproveneffectiveatreducingenergy costs.FIREPLACESManyfireplacesareveryinefficient.Theyoften usemoreenergythantheysupplyintermsofheating, especiallyiftheyusetheinsideairforcombustion ratherthantheirownoutsideairsource.Fireplace insertsandglasscoverscanbepurchasedthat improveefficiency.Woodstovesareveryefficient, buttheyrequirealotofworkandtheymaynotbeas aestheticallypleasingasafireplace. Inmanyhomeswaterheatingcanaccountforup to30percentofthemonthlyenergybill.Thereare anumberofitemsthataredesignedtoheatwater efficientlyandreducecost.InSouthFlorida,heat recoveryunitscansupplywaterheatingforthelong coolingseasonatlowcost.Manyair-conditioner manufacturersofferapackagedealonair conditioningandheatrecovery.Someutility companiesmayofferrebatesforheatpumpwater heatingandsolarwaterheating. Withaheatpumpwaterheaterareductionin waterheatingcostofupto50percentcanbe obtained,providingfreeairconditioningatthesame

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BuildingandRemodelingtoSaveEnergy Page5time.Anideallocationisthekitchenwherealotof heatisgenerated.Heatpumpwaterheatersalsocan beplacedneartheexistingwaterheater.Locatedin agarageorutilityroom,thesecanbemountedso thatanopeningtakesadvantageofairconditioningin thesummer.Itisclosedinthewinterwhencooling isnotdesired. Solarwaterheatingmaybeagoodchoice, especiallyiftherearetaxrebatesandutilityincentives toreducecostfurther.PriortoJanuary1986,a40 percenttaxcreditwasgivenforsomesolarpurchases upto$10,000.Thesecreditsmaybereintroduced. Asolarsystemshouldbeofpropersize,receive sufficientdirectsunlight,andbeinstalledcorrectlyto giveitanattractiveappearance.Inmostcasesthe collectorcanbeplacedflatontheroof.Thesimpler thesystem,thelessisthechancethatthingswillgo wrong. Installationofwaterheatertimersgenerallyisnot ascost-effectiveaswrappingthewaterheaterwith extrainsulation.Ifnaturalgasisavailable,replacing awornoutelectricheaterwiththehighefficiencygas heatermaybeananswertoutilitycostsavings.This savingscanoftenequalorexceedthesavingsobtained byusingsolarwaterheating,heatrecovery,orheat pumpwaterheatingoptions. Carefulselectionofenergyconservationmeasures canprovidecomfortandsavingsandmayoffer additionalbenefitssuchasnoisereduction,security, andbeautyOtherpublicationsthatmaybehelpfulare Insulation:SelectionandInstallation(EES25), EnergyEfficiency:aMarketingTool(EES24),Whole HouseFans:BenefitsandDescription(EES32), WholeHouseFans:Installation(EES33),and SelectingaHeatPump(EI8).