ERV or HRV in Cold Climate Zones-This should end the Debate!
On the internet
you will hear many opinions whether to use an HRV or ERV in different climate zones. Recent studies have suggested
that ERVs should be used in cold dry climate zones because of improved comfort, no drain required for condensation and less
energy for defrost.
like the one below have shown that HRVs should be used in cold dry climates. Using energy modeling software and looking
at the energy savings and comfort benefits, a new map of where ERV or HRVs should be used has been developed.
Defrost-Typically an HRV will freeze if the temperature drops below zero degrees Celsius requiring
some form of defrost to be used, such as a preheater which uses energy or recirculation and does not provide fresh air. A
European manufacturer completed cold weather testing at a 3rd party lab and found their counter-flow ERV core started to freeze
below -8C compared with the equivalent size and shape HRV at just below zero C. The lower frost point results in the
ERV requiring less defrost, and thus saving energy and money.
No Drain Required-In
most conditions, an ERV will not produce any condensation, therefore saving the cost of the drain pan and installing a drain.
By using an ERV and avoiding drains, European manufacturers are able to install ERV units in the walls of a home, where
there is no place to put a drain.
field study on HRV and ERV performance for a range of summer conditions was carried out using the twin houses at the NRC Canadian
Centre for Housing Technology in Ottawa. The ERV was found to provide better humidity control (i.e.,
providing a lower level of indoor relative humidity), as well as lower air conditioning electricity consumption, measured
as the cumulative saving of 12% over a week.