How ERVs Exhaust Warm, Stale Air From Your Home

Posted On: July 07, 2013

Energy-efficient homes nowadays are often well-sealed against air leakage. While this is good for energy efficiency, it can be bad for indoor air quality. There are many potential sources of air pollutants in your home. If fresh air is not occasionally circulated in, they can seriously degrade air quality. Of course, simply opening a window and allowing hot or cold air inside ruins the point of having a well-sealed home in the first place. For ventilating fresh air into your home during uncomfortable weather, the best option is an energy recovery ventilator (ERV).


The benefit of ERVs is that they offer controlled ventilation that can transfer the desirable properties of the departing air to the air that’s being circulated in. This is accomplished in a heat exchange core that allows for effective energy transfer without mixing the incoming and outgoing air streams. In the summer, the outgoing air will absorb heat and humidity from the incoming air, while in the winter, incoming air will absorb the heat and humidity. This helps keep the humidity levels in the house at a more comfortable level and recaptures much of the energy that was used to heat or cool the interior air.

It does take some energy to run the fans in ERVs, so they will only result in energy savings if there is a big enough difference between the incoming and outgoing air temperatures.


ERVs can be purchased as wall- or window-mounted units, but are more common as whole-house units. For installation ease and cost, it’s best if the ERV can share ductwork with your central HVAC system, but make sure your ductwork doesn’t suffer from poor design or air sealing because these are common sources of significant energy losses in homes today.

If you are interested in an ERV for your home (or a related heat recovery ventilator – HRV) or want help with any other home comfort issues, please contact the experts at Ernst Heating & Cooling. We provide exceptional home comfort solutions to residents in the Edwardsville, Glen Carbon and Hamel areas.

Our goal is to help educate our customers in Hamel, Alton, Glen Carbon, Highland, Greenville, and Troy, Illinois and surrounding areas about energy and home comfort issues (specific to HVAC systems).  For more information about ERVs and other HVAC topics, download our free Home Comfort Resource guide. 

Image courtesy of Shutterstock

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