Why are bath fan dampers so lousy??
I just installed a couple of Panasonic WhisperGreen bath fans on a job, and before nailing them in I took a close look at the internal backdraft damper. I had two different types on the job... one had a curved plastic damper like a potato chip, the other had a flat piece of thin aluminum, which I am used to seeing. Both types had a gap all the way around the perimeter... not a large gap, but there was no foam seal there, and I'm sure these will let in a lot of outside air during the blower door test, as well as during some windy conditions. I have taken to installing inline butterfly dampers in some cases, and generally use Seiho wall caps to try to reduce infiltration. I'm not sure why the fans themselves don't have better dampers. Maybe I should be using a different brand of fan? What are the ultra-low-blower-door builders doing in this regard?
Posted Jun 17, 2011 12:16 PM ET
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