Exhaust, Supply or Balanced Ventilation?


Mechanical ventilation draws out pollutants and draws in make-up air in a controlled manner. A well-ventilated home enjoys the benefits of improved indoor air quality balanced with energy savings. There are three main strategies for controlled ventilation: exhaust, supply and balanced systems.



Exhaust ventilation removes pollutants at the source. An inexpensive and simple approach to ventilating a house, it works by forcing air out of the home to depressurize the interior and gain make-up air through passive vents. Because this ventilation system 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 very humid, contain pollutants or be too cold, leading to energy penalties for the home.



Supply ventilation dilutes pollutants. Another simple and inexpensive approach, this strategy uses a fan to pressurize a home, actively bringing outdoor air inside while squeezing out indoor air. Supply systems offer better control over pollutants in incoming air, as they only obtain outdoor air through specified vents. Pressurizing the house more readily forces out combustion gases and other pollutants. However, supply systems struggle with conditioning or removing moisture from incoming air, and can raise heating or cooling costs.


A Balanced Approach

Balanced ventilation is best. Balanced ventilation works by both actively exhausting polluted indoor air and actively drawing in fresh, outdoor air in a balanced, controlled ratio. Because the system uses more fans and ducts than either the supply or exhaust approaches, it is more costly. However, balanced ventilation is appropriate for all climate zones.


By coupling a balanced approach with an energy recovery or heat recovery ventilator (ERV or HRV), incoming air can be conditioned and dehumidified, saving on heating and cooling expenses for the home, while simultaneously improving indoor air quality.

Mechanical ventilation can take the benefits of a healthy home one step further by providing a controlled source of treated fresh air that balances indoor air quality with energy savings.

WhisperGreen Select™ provides a customizable all-in-one exhaust fan and fan-light combinations for clean and healthy indoor environments Learn More

Intelli-Balance™ 100 Energy Recovery Ventilator (ERV) is a customizable balanced air solution that provides clean indoor air quality and lets you choose airflow with balanced, positive or negative pressure  Learn More

WhisperSupply is the only supply fan that cleans the air as it comes in. WhisperSupply filters outside air through a Merv 8 filter to a deflector that pushes air up and around the walls to avoid drafts and improve comfort Learn More