A108.1 General. Tables A108.1(1) and A108.1(2) list effective air change rates and heat capacities for heat loss due to infiltration for Single-Family Residential.
The estimated seasonal average infiltration rate in air changes per hour (ACH) is given for standard air-leakage control (see Section R402.4 for air leakage requirements for Single-Family Residential). The effective air change rate shall be used in calculations for compliance under either the Component Performance or Systems Analysis approaches.
Heat loss due to infiltration shall be computed using the following equation:
ACHeff * HCP
Heat loss due to air infiltration.
The effective air infiltration rate in Table A108.1(1)
The Heat Capacity Density Product for the appropriate elevation or climate zone as given below.
Assumed Effective Air Changes
Air Changes per Hour
Default Heat Capacity/Density
Product for Air
Mean Sea Level
0.0180 Btu/h • °F
0.0168 Btu/h • °F
0.0162 Btu/h • °F