Heat Recovery Ventilation:

The EPA says that indoor air is 3 to 5 times more polluted than outside air. In older, drafty homes, fresh air seeped in haphazardly just as heated air escaped to the great outdoors. With a tightly built envelope, a quiet, dependable system automatically delivers fresh air where and when it is needed, and removes stale air from the home. In the process, the system transfers 80% of the heat from the exhaust air to the incoming fresh air. In summer, if the outside temperature is higher than inside, the system works in reverse, removing heat from the incoming air. In this home, the entire ventilation process is centrally controlled. A schedule of air exchanges keeps the air fresh and exhausts stale air that might carry allergens or pollutants. Humidistats in the baths and laundry call for extra cycles when they sense the need to expel damp air. Particular attention is paid to air quality in the bedrooms, where the occupants spend so much time.