Performance of passive ventilation systems in a two-storey house.

Air change rates were measured in one two-storey detached house with five basic types of passive ventilation systems: an intake vent in the basement wall, an outdoor air supply ducted to the existing forced air heating system, an exhaust stack extending from the basement to the roof, and two combinations of the supply systems and the exhaust stack. An expression was developed for estimating house air change rate from house airtightness, neutral pressure level and indoor-outdoor air temperature difference. Good agreement was obtained for the test house between the predicted and the measured air change rates. The effects of furnace fan operation, air distribution system, and sizeand location of vent openings on house air change rates are also discussed.