Input | Value | Source |
Conditioned Area | 1915 square feet | Weighted average total conditioned square feet of Texas single family detached Single Family Dwelling (SFD) homes. |
Site Plan | 1 story square, 43'9'' × 43'9'' | 78% of Texas SFD homes are 1 story per 2009 Residential Energy Consumption Survey (RECS) [15] ; a square home is agnostic to orientation. |
Bedrooms | 3 | Majority of SFD homes (53%) have 3 bedrooms. |
Bathrooms | 2 | A plurality of SFD homes (41%) have 2 bathrooms. |
Foundation | Slab-on-grade, no insulation | Majority (76%) of SFD homes have a slab. |
Ceiling Insulation | For Air Infiltration measure R-22. For Ceiling Insulation measure: Base R-2.5, Change R-30. | The average ceiling/wall insulation level for homes existing before 1998 is R-20.51/10.94, per utility baseline studies. It is assumed that all homes built from 1998 on had an average of R-30/13, per International Energy Conservation Code (IECC) 2009 code requirements. Per [15] , 78% of Texas SFD homes are pre-1998, and 22% were built on or after 1998. Taking the weighted average U values of insulation, the result is an overall average of U-0.0882/0.0454, or R-11.3/22.0. |
Wall Insulation | R-11.3 | See above. |
Window Area | 210 square feet | Per [15], the average Texas home has 14 windows, assuming an average size of 3’ × 5’ that makes for 210 square feet of windows. |
Air Infiltration | For Ceiling Insulation measure: 12.2 ACH50 For Air Infiltration measure: Base 12.2 ACH 50, Change 7.43 ACH50 | Based on LBNL’s ResDB [16] , US average of 0.61 Normalized Leakage (NL) rate for SFDs; per ResDB [16] 0.5NL = 10 ACH50, so 0.61 NL = 12.2 ACH50. |
Window U-Value | 0.78 | Combined the prevalence of single, double, and triple paned glass in Texas SFDs from [15] (58/41/1%) with the average U and solar heat gain coefficient (SHGC) for each pane level from LBNL’s RESFEN database [17] , excluding windows with high solar gain coatings. |
Window SHGC | 0.56 | See above. |
Thermostat Settings | Heating: 71.3˚F during the day when someone is home, 67.7˚F during the day when no one is home, 69.8˚F at night; Cooling: 74.1˚F during the day when someone is home, 76.6˚F during the day when no one is home, 73.9˚F at night. | Weighted average reported thermostat set points from [15] . Times associated with these set points are assumed to be the same as those specified by Energy Star program in US. |
Duct Losses | 18% total loss | From LBNL’s ResDB [16] . National average total duct leakage is 18% of air flow. |
Air Conditioning | 11.3 SEER | Result of combining the average age of central cooling equipment from [15] with annual shipment-weighted SEER values from the US DOE. |
Electric Heater | COP of 1 | Fundamental property of electric resistance. |