Ventilation Strategies

Choosing the proper ventilation approach for healthier homebuilding

For home builders and contractors seeking to deliver healthy homes, installing powerful ventilation that assures good indoor air quality and energy efficiency is a must. At a recent homebuilding trade conference, many top green builders ranked the indoor air we breathe just as important to our health as the food we eat.

Exhaust, supply or balanced ventilation: Which strategy is best?

An effective indoor air quality solution requires more than a single exhaust fan in the bathroom. There are three primary strategies for controlled ventilation: exhaust, supply, and balanced systems.

Exhaust Ventilation

Exhaust ventilation removes pollutants at the source. An inexpensive and simple approach to ventilating a house, it works by drawing up and forcing air out of the home. A common example would be an exhaust fan in a bathroom or kitchen. Exhaust fans depressurize the home’s interior, which then gains make-up air through passive vents such as air leaks in the building envelope.

Because this strategy only actively exhausts air, it is not recommended in hot or humid climates. Since any make-up air is gained passively, that air may be humid, contain pollutants or be too cold, leading to energy-rating penalties for the home and discomfort for occupants.

For more information, visit our exhaust fan solutions.

Supply Ventilation

Supply-only ventilation dilutes pollutants. Another simple and inexpensive approach, this strategy uses a supply fan to pressurize a home and actively brings fresh outdoor air inside. Supply ventilation offers better control over pollutants present in incoming air, as they only obtain outdoor air through specified vents. Pressurizing the house more readily forces out combustion gases and other contaminants.

The downside? Supply ventilation struggles with conditioning or removing moisture from incoming air, and can raise heating and cooling costs due to leakage. This is particularly prevalent in older homes where building envelopes are more porous compared to today’s more tightly sealed energy efficient structures.

For more information, visit our supply ventilation solutions.