Describes a procedure developed for calculating the average annual air change rate of a house based on a measurement of the airtightness of the house and a single parameter that expresses the effect of the local weather on infiltration. States the procedure has been made simple so that it can be applied conveniently by contractors or building code officials without the use of a computer. ASHRAE Standard Project Committee 136P is developing a standard 'A method of determining air change rates in detached dwellings for indoor air quality purposes' which embodies this procedure.

KEYWORDS: Housing, USA, standards, air change rate, dwellings, indoor, air quality