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Community and Q&A

ERV as a bathroom vent fan?

mculik5 | Posted in Mechanicals on

My wife and I are purchasing a new house. House is in NJ and was built in 1987. Stick framing, average to slightly above average construction quality, average energy efficiency as far as we can tell.

For whatever reason, none of the bathrooms have vent fans. Putting fans in is likely to be one of the first projects I do.

Simple question – is an ERV appropriate to use as bathroom ventilation in a not-so-tight house? Our priorities are as follows:

#1 remove moisture to reduce mirror steaming and mold potential
#2 energy efficiency in terms of not wasting heated/cooled air
#3 low noise
#4 comfort

Will an ERV accomplish these things?

I’ve been looking at the Panasonic FV-04VE1, but it’s rating is 40CFM vs. most bath fans are a lot more than that. As an example, the largest bathroom in the house is 960 cubic feet, which conventional wisdom says needs a ~150CFM bath fan. Will 40CFM through the ERV be enough to keep the steam down during a shower?


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  1. user-2310254 | | #1

    Matt. I have posted on this topic before. You do not want to use the Panasonic ERV in a moist area. It will fail almost immediately. This unit also seems to deliver about half its rated CFM.

  2. GBA Editor
    Martin Holladay | | #2

    Either an ordinary bathroom exhaust fan or an HRV is a better choice than an ERV for removing moisture from a damp room.

    For more information, see these two articles:

    Bathroom Exhaust Fans

    Does a Home with an HRV Also Need Bath Fans?

  3. STEPHEN SHEEHY | | #3

    Matt: We have an hrv in our house in Maine. When we shower,we use the boost function and it handles the moisture just fine.

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