Air infiltration in residences accounts for 30 to 75 percent of the heating load, and present design procedures in commercial buildings result in excessive amounts of controlled fresh air introduction to offset air exfiltration losses. Simulation studies on retrofit potential of residences reveal that, while portions of the building heating and cooling loads can be reduced substantially using cost-effective techniques, air infiltration remains a dominant factor in the loads.

With the advent of a priority status for energy conservation, many new standards have been developed. These standards have been of three primary natures: prescriptive, component performance, and performance. Because new residential designs are making buildings tighter, with less air infiltration, three new standards are necessary to follow the trend in design. These standards are: (1) the use of pressurization-evacuation test methods to set a construction quality performance standard, (2) the use of ducted outside air with heat recovery for fresh air introduction to super-tight residences, and (3) the use of ducted outside air to fossil-fuel burning units for combustion purposes.