Add rim joist insulation 109 61% Add solar hot water system 109 61% Add photovoltaic 108 60% Add foundation wall insulation 91 51% Increase oil boiler AFUE 83 46% Add vaulted ceiling insulation 78 43% Add duct insulation 78 43% Reduce duct leakage 74 41% *Note that central heating systems were upgraded for a portion of the sample. While ductless mini-splits were included in every model they were sized to meet the cooling load of each home, not the heating load. As a result, the existing heating equipment was modeled to fulfill the remainder of the heating load and was upgraded where applicable. Table : Measures Included in Comprehensive Technical Potential Model Run—Less Common* Measure Sample Size % of Sites Upgrade freezer 60 33% Install ECM fan motor 53 29% Upgrade dehumidifier 49 27% Replace gas storage water heater with instantaneous 43 24% Replace tankless coil with indirect water heater 43 24% Replace electric DHW with heat pump DHW 42 23% Add DHW pipe insulation 39 22% Increase oil furnace AFUE 29 16% Increase gas furnace AFUE 26 14% Increase gas boiler AFUE 24 13% Replace oil storage DHW with more efficient oil storage 9 5% Replace LP storage water heater with instantaneous 6 3% Install air source heat pump 4 2% Increase propane furnace AFUE 2 1% Increase propane boiler AFUE 2 1% Replace gas storage DHW with more efficient gas storage 0 0% Replace gas storage DHW with gas condensing 0 0% Replace LP storage DHW with more efficient LP storage 0 0% Replace LP storage water heater with LP condensing 0 0% Upgrade central air conditioner 0 0% Upgrade room air conditioners 0 0% Install ground source heat pump 0 0% *Note that central heating systems were upgraded for a portion of the sample. While ductless mini-splits were included in every model they were sized to meet the cooling load of each home, not the heating load. As a result, the existing
Table : Features of Fuel Switching Groups Group n % Location Heating Fuel Heating Equipment Water Heating Existing After Switch Existing Switch Base Case Upgrade Case Group A 49 27% with gas service Oil or propane Gas Oil or propane boiler Gas boiler Conventional gas storage heater On-demand gas water heater Oil or propane furnace Gas furnace Group B 65 36% Towns with gas service Oil, propane, electricity, or biomass Electric with Existing Backup Oil, propane, or biomass boiler DHP* with existing boiler backup Existing water heater Heat pump heater Oil, propane, or biomass furnace DHP* with existing furnace backup Electric resistance DHP* with electric resistance backup Group C 20 11% Towns with no gas service Oil, propane, electricity, or biomass Electric with Existing Backup Oil, propane, or biomass boiler DHP* with existing boiler backup Existing water heater Heat pump water heater Oil, propane, or biomass furnace DHP* with existing furnace backup Electric resistance DHP* with electric resistance backup Gas Sites 46 26% with gas service No switch No switch No switch * “DHP” stands for “ductless heat pump,” or ductless
Replace electric DHW with heat pump DHW 42 2.3 EF Replace gas storage water heater with instantaneous 43 0.93 EF Replace gas storage DHW with more efficient gas storage 39 0.8 EF Replace gas storage DHW with gas condensing 39 0.9 EF Replace LP storage water heater with instantaneous 6 0.93 EF Replace LP storage DHW with more efficient LP storage 4 0.8 EF Replace LP storage water heater with LP condensing 4 0.9 EF Increase water heater tank wrap R-value 102 R-10 tank wrap Install low-flow showerheads 180 Calculated 2013 HES Program Savings Documentation Install faucet aerators 180 Add DHW pipe insulation 138 A: Lights & Appliances Measure Upgrades (Base: All applicable homes) Measure Sample Size Upgrade Upgrade refrigerator 180 319 kWh/year Upgrade freezer 60 188 kWh/year Upgrade dishwasher 164 1.28 EF, 170 kWh/year Upgrade clothes washer 177 Calculated 2013 HES Program Savings Documentation Upgrade dehumidifier 49 2.6 EF Increase socket saturation of efficient lighting 180 Increase saturation to 100% A: Heat Pumps & Solar Technologies Measure Upgrades (Base: All applicable homes) Measure Sample Size Upgrade Value Install ground source heat pump 103 17.1 EER, 3.6 COP Install air source heat pump 104 22.1 SEER, 11.3 HSPF Install ductless mini-split 180 12.1 EER (19.2 SEER), 3.0 COP (10.3 HSPF) (modeled as GSHP. See Appendix B for details) Add photovoltaic 108 South-facing 7.1 kW system, 35o tilt with 95% inverter Add hot water system 109 66 s.f., south-facing, double-glazed, liquid indirect system Maximum R-value Achievable by Framing Insulation upgrade values were assigned by determining the maximum R-value achievable with blown-in insulation in the framing found on site. Table A-6 details the insulation upgrade values by framing depth.
Table A6: Insulation Upgrade Values by Framing Type (Base: All applicable homes) Measure Sample Size Upgrade by Framing Type 2x4 2x6 2x8 2x10 2x12 Attic insulation 166 R-38 Vaulted ceiling insulation 75 n/a R-19 R-25 R-32 R-38 Wall insulation 165 R-12 R-19 n/a n/a n/a Foundation wall insulation 91 R-10 or R-13 Frame floor insulation 161 n/a R-21 R-30