Would venting a bathroom exhaust fan into the attic and through the attic window cause any problems? I was thinking this would prevent cutting a hole in the roof or the soffit. My thought was to insert the vent through a pane of glass. The window is old and that attic is large(it could actually be a room). Also, should the windows in an attic be well air tight?

1 Answer 1


This could be an option, as long as a few conditions are met.

There should be a damper

A damper will prevent outside air from entering the exhaust pipe, traveling down the length and entering the conditioned space. Most exhaust vent covers are designed in such a way, so that even on windy days the exhaust can still be exhausted. If you just have a pipe pointing to the outside, it's possible the outside air pressure can overcome the exhaust air pressure preventing the exhaust from exhausting.

There shouldn't be a way for the exhaust to reenter the building

If you simply close the window on a pipe that does not completely fill the opening, it's very likely that air pressure differences will force the exhausted air right back in the window. You'll want to devise a way to prevent the exhausted air from reentering the building. This other answer illustrates a way to install the vent, while blocking the entire window opening.

  • With the use of a damper this sounds like a possible solution. Additional recommendations are also appreciated. I didn't realize how tricky venting through the attic could be!
    – stephanie
    Commented Jun 7, 2013 at 14:01

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