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HRV used when only an ERV is needed

Ryan Lenz | Posted in Energy Efficiency and Durability on

My electrician has an HRV that was leftover from a different job and is willing to cut me a very good deal on it. Its a Panasoni WhisperComfort FV-04E1.  

I live in a low humidity area (central Oregon, zone 5B, cold dry winters and hot dry summers).  I realize the humidity regulation aspect of the HRV is not needed — i.e. an ERV is probably more suitable. 

(This is for a small 750 sq ft home heated by radiant floor heating supplemented by a mini split — no central furnace)

But, since its a good deal and appropriately sized, why not?

I was even thinking if someone wanted to, they could probably/possibly just remove the capillary portion of the unit? (The “enthalpy core” I think they call it?).

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Replies

  1. Expert Member
    Dana Dorsett | | #1

    >" I realize the humidity regulation aspect of the HRV is not needed — i.e. an ERV is probably more suitable. "

    I think you're reversing the sense of ERV & HRV. An HRV doesn't do any humidity transfer, an ERV transfers both heat and moisture. The FV-04E1 is an ERV. You really want an HRV (sensible-heat only, not humidity.)

    The core of the FV-04E1 can be damaged by frost, and it can't run optimally in a 5B climate. Most of the winter it will run a large fraction of the time, as exhaust only, since indoor humidity would otherwise build up as frost in the core when it's cold outside. When it's under 20F it self-protects with internal dampers that turn it into an exhaust-only unit to prevent the core from frosting up on the incoming cold air stream. Between 20F and 32F it cycles from exhaust only to ERV on a duty cycle, and only returns to a full ERV when it senses an outdoor temp higher than 37F. See page 7 of the manual:

    ftp://ftp.panasonic.com/ventilationfan/fv04ve1/fv-04ve1_en_installation.pdf

    >"I was even thinking if someone wanted to, they could probably/possibly just remove the capillary portion of the unit? "

    Sure you could, but it wouldn't ventilate any better than a couple of holes in the wall if you did. There's only ONE core, transferring BOTH heat & humidity. Remove the core and you'll just have a couple of fans beating against each other, short-circuiting the path.

    1. Ryan Lenz | | #2

      Hi Dana -

      Yes, I wrote that incorrectly -- I do *not* want an ERV, I just want an HRV.

      It sounds like this FV-04E1 unit, being an ERV, is going to give me problems in the winter due to indoor-generated humidity freezing up on the unit. Darn. Guess I'll have to pass it up.

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