Heat Recovery Ventilators

by Scott and Patti
(Upstate NY)

We are looking to install a heat recovery ventillation system (HRV) in our home (new construction)and couldn't find any useful information on benefits and costs. Do you have any opinions about them?


Hi Scott and Patti,

Here is my opinion:

- I don't have any experience living with HRVs but I have seen and recommended them in many new houses and retrofits. We heat with a high efficiency boiler and cool with central air that has a whole house fan and ductwork. So, in the and summer, we run the house fan, as well as bedroom ceiling fans alternatively to circulate preheated air or pre-cooled air.

If you have a furnace with ductwork, they are definitely useful for airtight houses - I think especially for new construction since you are doing everything at once and will save labor costs.

In many houses, windows don't sufficiently balance out air pressure, nor do they supply enough fresh air. I routinely run the whole-house-fan from the attic to supply fresh air and pressure.

- I like heat recovery ventilators that have heat and moisture recovery (energy recovery), since in the winter time you may end up with air that is too dry and then need to use a humidifier. Depending on where, when and how much you use the system, you might be able to save about 10-25% on heating and cooling costs, even though they need electricity to power the fan, especially if they are on 24/7.

-You need to remember to replace the filters on them or buy the reusable HEPA ones that can be washed.

- Also, depending on the type of furnace blower motor you have (is it single, double or variable speed) the amount of heat recovery may not make much of a difference during certain times, but that's probably when you are out of the house.

- Since you have a new house and the ductwork is there, it shouldn't cost too much to install it (<$2,000?).

I like this article (it's old but still relevant) on HVRs:

http://www.extension.umn.edu/distribution/housingandclothing/dk7284.html

Hope this helps :-)

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Oct 31, 2011
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Energy audit FIRST
by: Sustainable Guy

An HRV is only required if you are not getting enough fresh air exchanges in your home. There's no value in installing an HRV if your house is already quite leaky. You need to get a home energy audit in which they do a blower door test to determine how leaky your envelope is. If your Air Exchangers/Hour run below .3 then you need and HRV. If not then it makes more sense to tighten up the envelope FIRST, THEN evaluate the need for an HRV. Caulking and sealing are cheap, and should be the first step in improving the performance of your home.

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