The UltimateAir® News


Posted on Tue, Jan 08, 2019

Energy Recovery Ventilation or Heat Recovery Ventilation?


There is quite a bit of debate out there as to where ERVs should be used and where HRVs should be used. For those of you who do not know, HRVs, or heat recovery ventilators, like ERVs, are ventilation systems that transfer heat. However, unlike ERVs, heat recovery systems do not transfer moisture. This aspect significantly reduces HRVs capabilities in comparison to ERVs, making energy recovery units the more logical choice.

We see a lot of maps claiming that ERVs should be used in the humid South to reduce incoming moisture, while HRVs should be used in the colder North. However, these maps are inconsistent (for example, some suggest HRVs should be used in the arid Southwest). Moreover, they are wrong; ERVs can and should be used everywhere. As our graphic playfully shows above, we believe HRVs are suited for the Bermuda Triangle.


While the "Bermuda Triangle" comparison might be something of a hyperbole in regards to HRV ventilation, instances where an HRV would make more sense are few and far between. If you do not need to actively increase or decrease the humidity level inside your home at any time during the year, then sure, an HRV would be an acceptable choice. At the same time, so would the ERV because you will not just be using the moisture transfer ability.

But the claim that ERVs are inferior outside of humid regions is just untrue. By transferring moisture as well as heat, energy recovery ventilators effectively assist moderate indoor humidity for optimal comfort and safety. Buildings in dry, southwestern states that need humidity benefit from ERVs. Homes in cold, northern states would suffer similarly without retaining some humidity inside.

The myth that HRVs are preferred in northern areas is based on a freezing problem that ERVs experienced twenty years ago. This problem has long since been corrected, with current models featuring updated technology. However, some still use this outdated claim as a misleading justification. The HRV industry survives on this misinformation.

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Energy Recovery Units Are the Clear Choice

ERVs’ capability for moisture transfer, often referred to as enthalpy transfer, occurs with minimal mixing of the two air streams that are coming into and out of a home or business. This transfer permits moisture from the stream that is more humid to transfer to the stream that is drier. This is something heat recovery systems simply can’t provide

Energy recovery ventilators are more efficient and practical. They are the ventilation system of choice for Passive Homes and commercial buildings. If you are making the investment for your health and your home, why would you go halfway? Unless you’re in a place where the laws of physics don't apply, like the Bermuda Triangle, there’s no reason to choose a less functional system.

When it comes to ERVs vs. HRVs, ERVs are the way to go.

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You can view our energy recovery ventilators – the most efficient systems on the market – on our products page. And if you have any questions or are ready to install a unit, be sure to reach out to our experienced team. We’ll be happy to help!

Topics: indoor air quality, Home, ERV, energy efficient, Air Ventilation System, HRV, ERV or HRV