Describes a study conducted to compute the air exchange rates between the basement, main level, and ambient surroundings of an unoccupied single-storey detached house under various typical operating conditions. Using tracer gas techniques, the interzonal air exchange rates were predicted for the cases where (1) no fans were used to calculate air within or between the two zones, (2) air circulation within each zone was enhanced by operating auxiliary mixing fans, and (3) the furnace fan and auxiliary mixing fans were used to enhance air circulation within and between the two zones. A computer program was written to predict tracer gas concentrations in each zone of a two-zone building. To assess the accuracy and sensitivity of the computed air exchange rates, experimental tracer gas profiles were compared to simulated tracer gas profiles generated by the computer program. Results obtained from this study indicate that tracer gas methods used to quantify air exchange rates between the basement and main floor of the house may be inaccurate, especially if the tracer gas concentrations in each zone are not well mixed.

KEYWORDS: Air flow, housing, measuring, tracers, calculating, accuracy, computer programs comparing, air change rate, experiment.