Can you vent an exhaust fan in a basement bathroom out the sidewall rather than the ceiling? If I vent it through the ceiling I would have to cut through 3 joists to vent my exhaust fan outside and tie it into an existing clothes dryer vent.

  • Hello, and welcome to Home Improvement. How would you get the air to the sidewall; through the eaves? May 6, 2020 at 15:23
  • Will the fan itself be mounted in the wall, or just the exhaust vent?
    – isherwood
    May 6, 2020 at 17:50

2 Answers 2


Yes you can mount the fan on the wall. if the wall exhausts to the outside it would be no different than a wall mount exhaust vent in the main floor bathroom. You cannot mount it on an internal wall and just dump the air into a stud bay (I have seen this tried and failed).


You can not

tie it into an existing clothes dryer vent.

"The reasons being that you can't easily prevent backflow and you increase fire spread risk". ( Isherwood ).

Do your joist bays not run to an exterior wall ? ( there are specific restrictions on how big a hole you can put in a joist. )

You can mount a made for a ceiling fan and route the duct to and through an exterior wall.

You can mount a made for a wall fan on an exterior wall.


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