Air infiltration is the uncontrolled leakage of air into a house, that results from pressure differentials across its envelope induced by wind and inside-to-outside temperature difference. It is recognized as one of the major energy losses in residences but is difficult to estimate.

Infiltration rates can be measured using the tracer gas method which requires expensive equipment and long preparation time, but it is difficult to use on a large scale for routine tests. A more simple method is to use the fan pressurization method to conduct air leakage tests and then translate the result into infiltration rates using an infiltration-air tightness correlation. This paper introduces such a correlation for houses in a suburban area. A preliminary study of the proposed correlation has been reported previously. The final result is now presented.