Selecting An Energy Efficient Rental Unit

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Title:
Selecting An Energy Efficient Rental Unit
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.

Notes

Acquisition:
Collected for University of Florida's Institutional Repository by the UFIR Self-Submittal tool. Submitted by Melanie Mercer.
Publication Status:
Published
General Note:
"EES-34"

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Source Institution:
University of Florida Institutional Repository
Holding Location:
University of Florida
Rights Management:
All rights reserved by the submitter.
System ID:
IR00004800:00001


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Florida Energy Extension Service TheInstituteofFoodandAgriculturalSciencesisanEqualOpportunity/AffirmativeActionEmployerauthorizedtoprovideresearch,educational informationandotherservicesonlytoindividualsandinstitutionsthatfunctionwithoutregardtorace,color,sex,ornationalorigin. FloridaCooperativeExtensionService/InstituteofFoodandAgriculturalSciences/UniversityofFlorida/ChristineTaylorStephens,DeanSelectinganEnergyEfficientRentalUnit1GaryCook2Utilitycostscommonlyexceedonethirdofthe rentexpensefortenants.Renterswhopayforutilities cansignificantlyreduceoverallmonthlycostsof rentingbyselectinganenergyefficientunitwith featuresdescribedhere. Rentalunitsmaybebrokenintothreemain categories:1)ahouse,duplex,orsinglestory apartment;2)amultistoryapartmentcomplex;and3) mobilehomes.InFloridathereareseveralfeatures commontoallthree.ORIENTATIONEnergywillbesavediftheunitfacessouth.That is,thelongaxisorthesideoftheunithavingthe mostwindowsshouldfacethesouth.Thenextbest orientationwouldbetofacenorth.Thenarrower portionsoftheunitshouldfaceeastandwest.Facing southwillprovidesomepassiveshadinginthe summerandpassiveheatinginthewinter.Thisoccurs becauseofthesun'sapparentmigrationtothenorth insummerandsouthinwinter.Eastandwest orientationsarepooroptionsinFlorida. Themostefficientapartmenttyperentalwouldbe onethatfacessouthandthathasaunitover,under, andtoeachside.Inotherwords,itwillhavetheleast areaexposedtooutsidetemperatures.Adjacent apartmentswillgenerallybenearthesame temperaturesdesiredsothatthereislittleenergyloss. Ontheotherhand,ifthewallsandceilingsare exposedtooutsideconditions,theywillbesubjected totemperaturesover95degreesFinthesummerand nearfreezinginthewinter.Thetopsouthwestand southeastunitswillbetheleastenergyefficient becauseofsolarradiation.WINDOWDESIGNANDVENTILATIONWindowdesignandventilationareveryimportant inFlorida.Excessivewindowareascanwaste tremendousamountsofenergy,particularlyifthey faceeastorwest.Onahotsunnyafternoon,a windowwithanareaof1squarefootthatfaceswest willadmitmoreenergythananentireinsulatedwall. Thebestwindowdesignextendsfromabout3to6 feetfromthefloor.Thisallowsviewingoutsidewhen eithersittingorstanding.Slidingglassdoorswaste largeamountsofenergy. Windowsalsoshouldbeopenabletoallow ventilation,particularlycrossventilationwhenplaced onoppositeoradjacentwallsprovidedtheyarenot tooclosetoeachother.Thereareabout100daysa yearwhenneitherairconditioningnorheatingis necessaryifthereisproperventilation. Awholehousefancanaugmentnatural ventilationbypullingingreatquantitiesofoutsideair throughwindowsandexhaustingitthroughthe ceiling.Ceilingfanscanalsoprovideapositivebenefit bothwithorwithoutnaturalventilation.SHADEAnenergysavingfeaturecommontoallthree rentaltypesisshade.Shadetreesandmanmade shadeontheroofandwallshelpcoollivingareas. Thisisparticularlyimportantformobilehomes,which usuallyhavemuchlowerlevelsofinsulationthan 1.ThisdocumentwaspublishedasFactSheetEES-34,FloridaEnergyExtensionService.Formoreinformation,contactyourcountyCooperative ExtensionServiceoffice. 2.EnergyExtensionSpecialistforBuildingConstruction,FloridaEnergyExtensionService,InstituteofFoodandAgriculturalSciences,University ofFlorida,Gainesville. TheFloridaEnergyExtensionServicereceivesfundingfromtheGovernor'sEnergyOffice.Theinformationcontainedhereinistheproductof theFloridaEnergyExtensionServiceanddoesnotnecessarilyreflecttheviewsoftheGovernor'sEnergyOffice.

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SelectinganEnergyEfficientRentalUnit Page2 eitherapartmentsorhomes.Exteriorshadeatthe windowsisveryimportant,intheformoftreesor landscaping,awnings,Bahamashutters,andsolar screens.THERMALINTEGRITYInsulationshouldbethenextfeaturetocheck. Thisishardtodetermine,butthelandlordshould verifyiftheunitisreasonablywellinsulated.Ahigh R-valueintheceilingandwallsisimportant.For apartmentsandhomes,R-19intheceilingandR-11 inthewallsareconsideredgoodoraboveaverage. Radiantheatbarrierswillenhanceconventional insulationsignificantly.Aradiantheatbarrieris usuallyabrightlyreflectivealuminummaterial designedtoinhibitthetransferofinfraredheat. Inadditiontocheckinginsulationlevels,one shouldcheckthetightnessofwindowanddoor closuresbythedollarbilltest.Ifadollarbillmoves freelythroughaclosedwindowordoor,energywill bewasted.Caulkingandweatherstrippingaround windowsanddoorswillalsosaveenergy.HEATINGThenextfeaturethatshouldbeinvestigatedisthe heatingandcoolingequipment.Naturalgasheating isgenerallymoreefficientandlessexpensivethan otherheatingoptions.Usually,heatpumpsarethe nextbestchoiceforefficiency,supplyingheatata lowercostthanoilorliquidpetroleumgas.The efficiencyofaheatpumpisratedbyitscoefficientof performance,orCOP.Thehigherthecoefficient numberthebetter.Anefficientheatpumpwitha COPof2.5willsupplytwoandonehalftimesmore heatthanelectricresistanceheatingusingthesame energy.Oilwouldbethenextoption,followedby liquidpetroleumheat.Finally,electricresistance wouldbethelastandmostexpensiveheatingoption.COOLINGIndeterminingairconditioningefficiency,the landlordcanbeaskedtoprovidefromthenameplate ontheunitormanufacturer'sdatatheseasonal energyefficiencyratio(SEER)andtheenergy efficiencyratio(EER).Thehigherthenumberthe better.AirconditioningunitswithanEERof9are almost30percentmoreefficientthanthosehavingan EERof7.WATERHEATINGSincewaterheatingusuallyaccountsforabout30 percentofthetotalenergybill,thissystemshouldbe lookedatclosely.Thewaterheatershouldbelocated inashelterednon-airconditionedspaceandshould haveaninsulatedjacketforextraenergysavings. Thermostatsshouldbesetatnohigherthan140 degreesFifthereisadishwasher,andmaybesetas lowas105degreesF.Solarwaterheatingwould probablybethemostefficientwaterheatingsystem, butsincemostrentalunitswillnothavethisavailable, thenextbestoptionwouldbenaturalgaswater heating.Heatingwaterwithnaturalgaswillonlycost aboutonethirdthatofheatingwithelectricityandis aboutonehalfofliquidpetroleumgas(LPG) expense. Aheatrecoveryunitisalsoanattractiveoption. Inthesummer,aheatrecoveryunitsupplieshot wateratnoextracosteverytimetheairconditioner orheatpumpisoperating.Heatpumpswithaheat recoverysystemofferadditionalsavingsinthewinter byprovidinghotwaterataboutonehalftoonethird thecostofanelectricwaterheater.Aheatpump waterheaterwillprovidehotwaterataboutonethird thecostofanelectricwaterheaterandwillprovide airconditioningatthesametime.Waterheatedwith oilorliquidpetroleumgasismoreefficientthan electricresistance.(Liquidpetroleumwaterheatingis somewhatmoredangerousthanlighterthanair naturalgas.Liquidpetroleumisheavierthanairand leakscouldaccumulatenearthefloor,becominga potentialfirehazard.)Electricresistancewater heatingistheleastefficienttype.APPLIANCESANDLIGHTINGAppliancesandlightingaccountforabout20-30% ofthemonthlyenergybill,andarefrigeratoruses moreenergythanotherappliances.Theoldermanual defrostmodelsaremoreenergyefficientthanself defrosting,althoughsomenewselfdefrostingmodels givebetterperformance.Refrigeratorcoilsbeneathor behindtherefrigeratorshouldbeclean.Washerand dryersshouldbeinanon-airconditioned,naturally ventilatedspace.Gasstovesgenerallycookmore efficientlythanelectricones.Thestoveshouldbe providedwithaventilatedhoodsothatheatand coolingvaporscanberemoved. Finally,bathroomsshouldhaveexhaustfansand beusedduringandafterbathingtopreventmoisture

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SelectinganEnergyEfficientRentalUnit Page3 buildupandmildewproblems,andfluorescentlights useonlyaboutonethirdtheenergyofincandescent lightsofthesamewattage. Thefollowingtablesarecheckofflistsforthe typeofrentalunitunderconsideration.Pointvalues foreachenergycharacteristicareinparenthesesand shouldbeenteredattherightandfinallytotaled.

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RentalEnergyEvaluation/ChecklistforHouse,Duplex,SingleStoryApartment,orMobileHome 1.Orientation ______ Facessouth(6);Facesnorth(4);Faceseast/west(0) 2.Shade* ______ Shadeonbotheastandwestwindowsandroof8 Shadeoneastandwestwindows/glass,notroof6 Shadeoneithereastorwestwallonly3 Nosignificantshade0 *Exteriorshade:solarscreen,Bahamashutters,reflectiveglass,trees(notcurtainsorvenetianblinds) 3.HeatingSystemNorthFL CentralFL SouthFL ______ Naturalgas1064 HeatpumpCOP2.87853 HeatpumpCOP2.2-2.7742 HeatpumpCOP2.2631 Oil532 LPG421 Electric000 4.CoolingSystem ______ EER9(10);EER8-9(8);EER7-8(6);EER6-7(4);EER6(0) 5.WaterHeater ______ Solar(10);Heatrecoveryorheatpumpwaterheater(6) NaturalGas(8);LPG(4);Electric(0) InsulatedJacket(add2points) 6.InsulationFrameConst. BlockConst. ______ CeilingR-19,wallsR-111014 CeilingR-11-18,wallsR-6-1059 CeilingR-10,wallsR-504 (Blockmaybe4valueslowerforwalls) 7.RadiantBarrier ______ Atticandwalls(5);Atticonly(3);None(0) 8.GeneralTightness,Weatherstripping,Caulking______ Good(6);Fair(3);Poor(0) 9.Ventilation ______ Wholehousefan(4);Ceilingfaninbedroomandlivingroom(3) Cross-ventilationinbedroomandlivingroom(2) 10.Lighting:kitchen,livingroom,bedrooms______ Fluorescent(1);Incandescent(0) TotalPoints______ Energy Rating NorthFlorida Points CentralFlorida Points SouthFlorida Points Excellent 60-74 57-71 55-69 Good 45-59 42-56 40-54 Fair 30-44 27-41 25-39 Poor 0-29 0-26 0-24

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RentalEnergyEvaluation/ChecklistforApartmentMoreThanTwoStories 1.Location ______ Southornorthunitwithunitsaboveandtoeachside(14) Southornorthtopfloorwithunitstoeachside(9) NW,SW,NE,orSEunitwithunitsabove(5) WorEunitwithunitsaboveandtoeachside(7) 2.Naturalormanmadeshade ______ East/westglassexposuresareshadedorapartmenthasonlynorthorsouthfacingglass(4) 3.HeatingSystemNorthFL CentralFL SouthFL ______ Naturalgas1064 HeatpumpCOP2.87853 HeatpumpCOP2.2-2.7742 HeatpumpCOP2.2631 Oil532 LPG421 Electric000 4.CoolingSystem ______ EER9(10);EER8-9(8);EER7-8(6);EER6-7(4);EER6(0) 5.WaterHeater ______ Solar(10);Heatrecoveryorheatpumpwaterheater(6) NaturalGas(8);LPG(4);Electric(0) InsulatedJacket(add2points) 6.InsulationFrameConst. BlockConst. ______ CeilingR-19,wallsR-11610 CeilingR-11-18,wallsR-6-1048 CeilingR-10,wallsR-504 (Blockmaybe4valueslowerforwalls) 7.RadiantBarrier ______ Atticandwalls(5);Atticonly(3);None(0) 8.GeneralTightness,Weatherstripping,Caulking______ Good(6);Fair(3);Poor(0) 9.Ventilation ______ Wholehousefan(4);Ceilingfaninbedroomandlivingroom(3) Cross-ventilationinbedroomandlivingroom(2) 10.Lighting:kitchen,livingroom,bedrooms______ Fluorescent(1);Incandescent(0) TotalPoints______ Energy Rating NorthFlorida Points CentralFlorida Points SouthFlorida Points Excellent 60-74 57-71 55-69 Good 45-59 42-56 40-54 Fair 30-44 27-41 25-39 Poor 0-29 0-26 0-24