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Community and Q&A

Bathroom fan vent – Outside air infiltration

DonB52 | Posted in General Questions on

I live in a very windy area and the roof vents for my bathroom fans allow quite a bit of outside air infiltration, cold air in the winter being the most significant comfort problem. Possible remedies might include a vent with a tighter flap, but I don’t know make and model of such better vents. Or perhaps a backdraft damper, but I don’t know how to select one that would be compatible with my bathroom fans in terms of not putting damaging strain on the fan motors. Any recommendations for a remedy would be appreciated!

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  1. Expert Member


    Do you have easy access to the ducts running from the fans, and do those ducts runs straight up, or is there a section that is horizontal?

    1. DonB52 | | #2

      I'll have to check on access to, and orientation of, the ducts. Do you have a particular solution in mind?

      1. Expert Member
        MALCOLM TAYLOR | | #3

        There are a lot more good options for inline dampers than there are for either those mounted at the fan, or the exterior terminations. Some of the inline dampers rely on being mounted horizontally.
        These work very well:

  2. PAUL KUENN | | #4

    All fans, even the excellent Panasonic have useless flapping gapped dampers. I use the butterfly style from Broan that seal much better but it does have to be horizontal. I like to vent to roof so I have the damper taped right to the plastic cheap damper then a 90 degree elbow straight up. Easier if your duct goes straight out horizontally.

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