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ERV or HRV

H W | Posted in General Questions on

I know an HRV is recommended here in my climate zone (Vancouver, BC, Canada) but an ERV seems to have so many more benefits and it is much cheaper!

The only downside to the ERV for me is that due to vapor being able to pass through the core, it can bring other elements that are dissolved in it!

In any case, good ERVs seem to be cheaper.

My other question is do I also need a dehumidifier if I get an ERV or HRV?

Any ideas of what I should use here? And any recommended products?

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Replies

  1. Expert Member
    Malcolm Taylor | | #1

    Hawnes,

    The main difference between them is that the ERV will also transfer moisture from the exhaust to the incoming air. Something that in a tight house in Vancouver can cause humidity problems. An HRV ventilating the house should be able to keep the indoor humidity in check. An ERV may need a supplemental dehumidifier to do that - which seems a bit of an odd arrangement - first adding moisture, then extracting it.

  2. Trevor Lambert | | #2

    All other things being equal, an ERV is usually more expensive. If you're seeing the opposite, I suspect it's because the units you're looking at aren't comparable.

  3. H W | | #3

    Ok great.

    Do any of you recommend a dehumidifier in my climate zone with an HRV?

    1. Expert Member
      Malcolm Taylor | | #4

      Hawnes,

      i would run the HRV at the prescribed level of ventilation and see where the house settles. My bet is it will reduce the humidity to an acceptable level on its own.

      1. H W | | #5

        I see. That's what my energy advisor has told me as well. But I worry that during the shoulder seasons the dew point will continue to climb as climate change gets worse and then the HRV will bring in humid air.

        1. Expert Member
          Malcolm Taylor | | #6

          Hawnes,

          Good p0int - and one I can't answer. Here on Vancouver Island my indoor humidity peaks during prolonged overcast conditions in the summer, and stubbornly resists attempts to lower it through ventilation. Maybe the option of dehumidification is worth including?

  4. H W | | #7

    Hi Malcolm, awesome didn't know you were in Vancouver Island, we are neighbours!

    Do you know how high your relative humidity was?

    1. Expert Member
      Malcolm Taylor | | #8

      Last August it was regularly in the low 60s. Right now my house is 49%.

      Pretty high winds coming your way around midnight tonight.

  5. H W | | #9

    Yea, here in Vancouver it wasn't quite into the 60s but it was pushing it. But I'm not sure how accurate my RH monitor was. I recently bought an Awair monitor so will have more accurate data. This will just get worse in my opinion!

    Haha, I'm ready for another power outage....

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