The key to indoor comfort in Passive House is a quiet central ventilation system that is widely used in Europe but still relatively unknown in the United States. As warm, stagnant air is expelled through the energy recovery ventilator, it passes by incoming streams of fresh, cooler air, allowing up to 90% of the heat to transfer without mixing the two streams of air. This system provides superior air quality 24 hours a day. Some European ventilation units not yet available in the US can provide all necessary heat for the house. As a result, says Passive House advocate Tad Everhart, “a passive house loses very little heat and then recycles it.”
