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.