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Planning for an ERV

Andris Skulte | Posted in General Questions on

I recently bought an Airthings Wave, and set it up in our bedroom. I figured we’d have high CO2 at night, and sure enough, first two nights were 1100, and last night stayed at 1900 after friends came for dinner… Now I’m thinking I need to add ventilation. Our last energy audit 10 years ago showed 1610 cfm at ACH50 (not super tight, but…). Since then I replaced the oil furnace with a few mini splits, and did some more sealing…

The house is a 1700 sq ft 1960’s cape in Connecticut (Zone 5), with two (ish) bedrooms in a dormered upstairs, and the rest of life downstairs (kitchen, LR, office, etc…). We have a full basement (unfinished) and crawlspace above the 2nd floor where I could probably fit a small ERV, like a Panasonic Whisper Spot, or maybe run 4″ flex ducts…

If I follow the .35 ACH guidelines, then I’ll need roughly 80 cfm.

Suggestions on how I should set it up? Anyone else been here before?


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  1. Steve Knapp CZ 3A Georgia | | #1


    Just out of curiosity, have you tried running a bath fan 24/7 and tracking your CO2 levels? I'm not wild about exhaust-only ventilation but...

    1. Andris Skulte | | #2

      Thanks for the reply, Steve. I'll do that, and report back (along with cracking open the bedroom window). Bath fan is downstairs (upstairs bath will get one when my honey-do list gets shorter!). Not crazy about adding an air leak to the house without trying to re-capture some of the heat being wasted, as well as very dry air in the winter.

      I'll do that, and see how much the CO2 level changes.

  2. chicagofarbs | | #3

    If you don’t want to run ductwork you could look at the Lunos E2

    They get installed in pairs and I believe up to 4 total can be controlled together.

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