High Efficiency Ventilation Systems that are correctly sized and installed help improve air circulation, maintain appropriate humidity levels, remove indoor pollutants, and increase the comfort, safety, and energy-efficiency of a home.

Legend

1. Air Sealing
2. Insulation
3. High Efficiency Ventilation System
4. Efficient Windows and Doors
5. Efficient Heating Systems

HAAS Consideration: A home with too little ventilation may result in issues identified in the Air Sealing HAAS Consideration. A home with too much ventilation may be uncomfortable, expensive to heat, and (if there are combustion heating systems or appliances) create issues with combustion spillage. The problem with homes with unbalanced (only exhaust) ventilation (standard bathroom fan and range hood) is that the supply air is coming through cracks in the building envelope; as a result, there is no opportunity to filter incoming air and there is potential to draw moisture into the building envelope.

The best option for ventilation in homes with appropriate levels of air tightness, is a heat recovery ventilator, which uses the air being exhausted to heat incoming air. Once a home has achieved an air tightness of 3 air changes per hour (measured at 50 pascals), or lower, a heat recovery
ventilator is recommended.