More often than not when I’m doing a home inspection and we come across an air exchanger, the client asks, “what is that thing and what does it do?”  An air exchanger helps to improve the indoor air quality in your home by continuously circulating fresh outdoor air in to your home while exhausting stale stagnate indoor air out of your home.  Effectively recycling the air you breathe.

Indoor air pollution

Homes today are sealed up very tightly to keep the heat in during the winter and the cold in during the summer.  Unfortunately sealing up houses also traps unwanted pollution in our home such as off gasses from combustion appliances, cleaning products, dust, pet dander, tobacco, radon, and pesticides.   Our homes today actually have more air pollution inside than they do outside.  You can read more about indoor air quality at  Another unwanted element is excessive humidity, which can lead to condensation and mold.  In the past we opened a window to circulate fresh air in our homes but obviously that isn’t very energy efficient and can be very costly on our heating and cooling bills.

How does an air exchanger work?

An air exchanger or Heat Recovery Ventilator (HRV) is connected to your forced air HVAC system.   It has two fans inside, one to exhaust stale air from the house, one to supply fresh air into the house, and a heat exchanger to transfer heat or energy from one airstream into the other.  During heating season the HRV mixes warm exhaust air with the cool intake air to increase efficiency.  During cooling season when the air conditioning is running it mixes the cool exhaust air with the warm intake air to increase efficiency.  So the air exchange function provides continuous fresh air to improve air quality and humidity levels and the heat exchange function improves efficiency of heating and cooling.  The continuous circulation of air in the home also provides more even heating and cooling and makes the home feel more comfortable.

Do you need an air exchanger?

I often recommend clients consider adding an air exchanger to a home during the home inspection process.  In our own home we had issues with excessive condensation on the windows during the winter that was leading to moisture damage.

We experienced some health effects such as intensified allergies, fatigue, stuffy noses, runny eyes, and sinus infections.  Even our pets were experiencing upper respiratory issues and asthma.  We consulted the folks at Ditter Cooling Heating and Electrical here in Minnesota.  After determining a need through indoor air quality testing an air exchanger was integrated with our heating and cooling system.  The first and most obvious improvement was that condensation and frost was eliminated from our windows during the winter, even in temperatures well below zero outside.  Indoor air quality tests after installation showed reduced particulates, radon, mold spores and humidity in the air.  Health effects for us and our pets lessened and we are more comfortable.   We can even tell if the system is not running within a few short hours based on how we feel.


Homes built in recent decades are sealed up tight to increase energy efficiency.  The drawback is that they also trap pollution in our indoor air.  An air exchanger may significantly improve your indoor air quality.  If you are buying a home in the twin cities or central Minnesota area, contact us at The Peerless Service Company to schedule an inspection.  We will help you determine the need for and benefits of an air exchanger.  If you are concerned about your own home consult with a reputable professional HVAC company near you to help determine what options are most suitable for you and your household needs.

Categories: Educational