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Bathroom vent fan with ERV/HRV in older house that isn’t the tightest.

user-1101118 | Posted in Energy Efficiency and Durability on

Performing a remodel/energy bolster on an older 700 sf house. I don’t want to go through the trouble of a whole house balance vent system. I am considering a bathroom fan w/ heat recovery, such as the Panasonic unit. My questions/concerns:
1_Climate zone 7 9000HDD. Will the core freeze? ERV’s I have installed on other projects cycle into recirc x minutes per hour to prevent this.
2_Will the panasonic unit effectively reduce moisture in the one bathroom given that it is an ERV?
3_Is there another brand besides panasonic, perhaps one that is an HRV with a drain line to get rid of the moisture?

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  1. GBA Editor
    Martin Holladay | | #1

    The Panasonic ERV is not recommended for cold climates like yours. See the map in this document:

    What you need is a Panasonic exhaust fan.


  2. mackstann | | #2

    I've seen some small passive HRVs that could work (passive as in no built-in fan), but it's a very expensive solution when the fan is only running 1 or 2 hours per day. I suspect it would never pay for itself in energy savings. However, it might keep the bathroom warmer and more comfortable.

  3. srivenkat | | #3


    Just curious. I am in zone "B" (East Central Illinois). If I installed this fan as a replacement for the exhaust fans in the bathrooms, could it freeze and refuse to even work as a simple exhaust fan?

    I could all Panasonic, but I know all that I would hear is what's mentioned on the map you cited.



  4. user-2310254 | | #4

    The Panasonic ERV will NOT work in a moist environment. (Don't ask me how I know.) As soon as the control board get wet(ish), the safety fuse blows. This is a soldered in fuse, BTW. Also, Panasonic will not warranty the unit if installed in a wet area. (Again, don't ask me how I know.) ;-)

    The Panasonic WhisperGreen bath fans with DC motors are very efficient, however.

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