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Community and Q&A

I just read the article on attic fans and it does not talk about moisture build-up during the winter months

Tom Borsodi | Posted in Energy Efficiency and Durability on

My home is 10 years old and I am getting moisture in my attic from the cold and warm air. My ceiling is getting water stains on the ceiling. My fire detectors even shorted out because of the moisture issue.
If an attic fan is a bad thing to use what would be the answer to eliminate the moisture build up I get during the winter months in Chicago?
Thank you

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  1. Andrew C | | #1

    The first thing that I would investigate is air sealing. Air leaking from your house into your attic can carry a lot of moisture. Also, if you have any bathroom vent fans that are exhausted through the attic, make sure the hoses/ducts aren't leaking air or actually condensing water and then leaking. (We had a friend upgrade an exhaust fan last week. They needed a bucket to empty water out of the uninsulated flex duct.)
    Could be something else, but those are two things that I would investigate.

  2. GBA Editor
    Martin Holladay | | #2

    The cause of your problems is almost certainly air leaks through your ceiling. It's also possible that you have an ice dam -- a problem that is also caused by air leaks through your ceiling.

    Warm humid air is escaping from your home. When the warm air enters your attic, the moisture in the air condenses on cold surfaces. If you seal the air leaks, you will solve the problem.

    These articles may help:

    All About Attic Venting

    Air Sealing an Attic

    Prevent Ice Dams With Air Sealing and Insulation

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