Segment 5: Ventilating an Air-Tight Home
When you construct an air-tight building, you need to provide ventilation. In a Passive House, all the air you breathe comes from a known source and has passed through a fine filter. In addition, the ventilation system has a special feature that captures most of the heat in the outgoing air and returns it with the incoming air. This is called Heat Recovery Ventilation or HRV. The HRV system enables the exchange of fresh, filtered air, removing dust, allergens, smoke and moisture.
In a conventional leaky building, air enters the building wherever it can find its way in rather than coming in through a filtered system. Because hot air rises and exits the building through the top, the incoming air you breathe often comes from the crawlspace and can carry dust, allergens and toxins it picks up on the way in.
