The UltimateAirĀ® News

Energy Recovery Ventilation or Heat Recovery Ventilation

Posted on Mon, Jul 23, 2012

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             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, like ERVs, are ventilation systems that transfer heat. However, unlike ERVs they do not transfer moisture.  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 in the arid Southwest). Moreover they are wrong; ERVs can and should be used everywhere.
           While the "Bermuda Triangle" comparison might be something of a hyperbole, 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 anytime 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 bad outside of humid regions is just untrue. By transferring moisture as well as heat, they effectively assist moderate indoor humidity for optimal comfort and safety. Buildings in the dry Southwest that need humidity benefit from ERVs. Homes in the cold North would suffer similarly without retaining some humidity inside. The myth that HRVs are prefered in the North is based on a freezing problem that ERVs experienced twenty years ago. This problem has long since been fixed. However, some still use it as a misleading justification. The HRV industry survives on this misinformation.

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? Maybe in a place where the laws of physics don't apply, like the Bermuda Triangle. Get lost HRVs.

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