Installing a Bathroom Vent Fan Through a Wall

We would like to install an exhaust fan in our bathroom to remove excess moisture but do not have an attic to vent it through. Can we install it in an outside wall instead, or are there vent fans available that don’t need an outside vent? -Barb

Hi Barb,

Wall mounted vent fans are available, though they’re not as common as ceiling mounted models and may be more difficult to install, especially if you have a brick veneer house. There are ductless vent fans that use a charcoal filter to remove odors, but they do not remove excess moisture, which is the main purpose of a bathroom vent fan. To remove excess moisture from your bathroom, the fan needs to vent outside.

Since a bathroom vent fan should run for 10-15 minutes after you finish your shower to remove all the moisture, consider a fan that cuts on and off automatically using a moisture sensor or replace the wall switch with a timer.

Good luck with your project,


Further Information

How to Size a Bathroom Vent Fan
Not Your Old Bath Fan
How to Maintain a Bathroom Vent Fan (video)


  1. today june 19 2010 i was watching your show on shower scum and soap scum
    you were using a car wax car window cleaner not very sure but what brand could you gvie me more infro.

  2. I would like to install an exhaust fan in a basement storage room to vent excess dust from cat litter boxes through the upper wall of the room to the outside. Can this be done?

  3. Hi Danny, Our house is 20 years old and we have a metal roof that we installed about 5 years ago. The builders never installed vent fans in the bathrooms. I want to install them without cutting through the metal roof, but is that possible? Can it be put on the wall and vented to the outside wall like a dryer vent is done?? Thank you for your help.

  4. There is no attic above the bathroom and a window takes up most of the outside wall. Can I tie the fan to the existing plumbing vent stack that goes through the roof?

  5. We have 2 bathrooms but only one has a fan that is vented out. The other bathroom fan blows into the bathroom not into the attic. Can I add the vent pipe to the fan that vents outside after I install 2 new modern vent fans?

  6. how long of a run can i install horizontally ducting to vent from the exhaust fan to the outside exterior wall? can I use exhaust flex pipe all the way or use of some solid metal piping all the distance?

  7. So I have a quandry…100 year old house no fan in the bath. Balloon construction prevents ceiling installation. Is there room in a 2×4 wall cavity?

    • Hi, Robin,
      Great question! We have forwarded it to the Today’s Homeowner Radio Show’s producer.
      He will contact you soon to discuss featuring it during an upcoming show.
      Take care!


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