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Blower door testing

bbirck | Posted in General Questions on

I just had my house, which is near completion, blower door tested with a result of 700 Cfm @ 50p and an ACH of 2.0. This was done with the HRV vents open.

Should I have sealed the vents fot the testing, and would that have made a significant difference?

There are 2 supply vents and 4 exhaust vents.

Thanks for your help.


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  1. davidmeiland | | #1

    Yes, intentional openings should be sealed off, and if you had done so you would have gotten lower numbers.

  2. bbirck | | #2

    Thanks David. That's what I was afraid of. Care to guess as to how much difference that might have made?

  3. davidmeiland | | #3

    It would probably be very significant. Wild guess... you're getting at least a few hundred CFM50 thru those inlets, and your real number is more like 1.5 ACH50.

    If you hired a tester, I might ask why he didn't seal the HRV ports. We did two units yesterday with HRVs and had to go around with a ladder and get all of them.

  4. jklingel | | #4

    Bill: Either way, you have nothing to worry about, so get your fishing equipment ready. Whoever built the place did well. j

  5. Michael Chandler | | #5

    2 ach 50 is fine in my opinion. vents open or closed. Enjoy your new home. My testers have been reluctant to seal those ports as well. Grrrr.

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