September 15, 2000


A multi-zone, single-gas, tracer gas decay measurement technique was used. A single-story, slab-on-grade 1350 sq. ft. house was tested in Las Vegas, Nevada, and a two-story, 3192 sq. ft. house with basement was tested in Minneapolis, Minnesota. The ventilation systems studied included various configurations of exhaust, supply, and balanced ventilation, with and without whole-house recirculation by the central heating and cooling air-handler unit fan. Some of the systems were independent of the central air distribution system, while others were integrated with it. In general, results showed that all ventilation systems benefitted from periodic operation of the central fan, giving excellent uniformity of ventilation air distribution. System without central fan recirculation showed poor ventilation air distribution for closed rooms where there was no ventilation system duct.