Frost Prevention in HRVs and ERVs in North America


There are several options for preventing frost in HRVs/ERVs, and the following is a sampling of the most popular options. It is important to have adequate frost prevention, and depending on your climate, there are best practices available. If you have questions about best practices for your region, contact Zehnder America for recommendations. Option One – Utilize a ground source Pre-Heater/Pre-Cooler. The Zehnder ComfoFond-L utilizes a ground loop of glycol and a small circulating pump to pre-heat or pre-cool and dehumidify

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ASHRAE Standard 62.2-2010


So much talk in the building industry these days seems to be about ventilation, and specifically, ASHRAE 62.2-2010. This is the standard that is being adopted by many states for code compliance, as well as by weatherization programs across the country.   With the new standard comes plenty of confusion, and plenty of scrambling to understand and implement the standard.  In reviewing the ASHRAE 62.2 -2010 standard, it becomes clear that compliance is a challenge with a conventional exhaust only (bath

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Combining HRVs/ERVs and Heating/Cooling


Zehnder has been dealing with this issue across the country, and newly collected data confirms our recommendation that you do not mix the two. There are two aspects of this practice that have had negative impacts on comfort, efficiency and healthy environments. 1)Heating/cooling the ventilation air The biggest drawback here has been the tendency to over-ventilate to meet heating or cooling needs.  In winter this can lead to drying out of the indoor air, and in summer this can lead to

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We are often asked, “Should I use an HRV or an ERV?”   Building professionals sometimes assume that the use of an HRV versus an ERV can be determined by geography, but it’s often not that simple. Much of the country uses an HRV and one could generalize that ERVs are better for humid climates, but what about those climates that are both dry and humid during the year?   For New England, often building professionals use an HRV, but one could realistically use

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