Ducts, Dampers, Registers and Valves
High-performance house ventilation systems are substantially different from old forced air heating systems which move large amounts of air. High-performance ventilation system ducts typically channel a smaller volume of air through smaller and shorter ducts. And, just like the Passive House itself, the ducts are airtight.
Unlike forced air heating systems, the ducts typically run through only conditioned areas and are uninsulated. Like forced air heating ducts, they are as free as possible of unnecessary restrictions that impede airflow. Some ducts provide not only fresh air and remove stale air, but also distribute heat throughout the house. However, their primary purpose is ventilation, and they are designed to operate 24/7 throughout the year—even in the heat of summer.