Energy efficient ventilation filters.

To ensure good indoor air quality in buildings, filters are installed in the ventilation ducts. These filters cause a pressure drop in the ducts, so that increased power to the ventilation fans is required to maintain the flow of fresh air. To reduce this problem, the Norwegian company, Interfil, developed a new energy efficient filter in 1995. This filter has been carefully tested in recent years. The test results show that, compared to ordinary filters, the new filters could reduce fan power by about 10%, while maintaining indoor air quality.