What is Controlled Ventilation?


Modern construction methods for low-energy and passive houses are characterized by high thermal insulation and minimized thermal bridges. The resulting tightness of the building envelope requires a regular active air exchange for the well-being of the occupants and for the protection of the building structure.

Ventilation systems with heat recovery provide the adequate air exchange for both, the occupants and the building structure at any time of day. Pollutants, odors, and excessive moisture are discharged and the supplied fresh air is filtered and free from dust and pollen. Environmental noise and insects will stay outside. At the same time, energy consumption is significantly reduced, compared to traditional natural ventilation.

The Zehnder heat recovery system for the controlled ventilation of living spaces consists of a heat recovery unit and an air duct system which supplies the house with fresh air, draft-free. Stale, odorous and moist air is extracted in the kitchen and bathrooms.

During the cold season, the heat of the extract air is transferred to the fresh air into the dwelling and therefore saves valuable heat energy. In the warmer time of year, a summer by-pass can provide fresh, filtered air without heat recovery.

The “heart” of every heat recovery unit is the heat exchanger (image below). It transfers the heat of the warm extract air to the cold intake air from the outside. The higher the heat exchange rate, the better the effectiveness of the heat exchanger and therefore, the saving of heat energy. Zehnder heat exchangers achieve the highest efficiencies.

The intelligent and user-friendly control of the ventilation system ensures adequate fresh air supply at any time, as well as high living comfort at low heating costs. With a ventilation system, you not only invest in comfort and energy savings but also in the long-term maintaining of your building structure.


Need more info on Zehnder America’s Heat Recovery Ventilators? Click here.