Tips on Where and How to Install a Bathroom Vent Fan

Is it better to install a bathroom vent fan in the shower or the middle of the bathroom? -Steve

As long as the wiring for your bathroom vent fans is attached to a Ground Fault Circuit Interrupter (GFCI) and the fan is rated for a shower area, the best place to locate your vent fan is on the ceiling in or near the shower where it will do the most good. Vent fans that include a heater, however, should not be installed over a shower.

Another consideration is that the fan should be located away from the intake air source, such as a door or window (if the window will be open). If the window and door will be closed, make sure there is a 5/8” or greater gap under the door to allow fresh air into the room.

Other vent fan installation tips include:

  • Make sure the vent fan moves enough cubic feet per minute (CFM) of air for the size of your bathroom.
  • Exhaust the air from the vent fan to the outside of the house, not in the attic.
  • Use smooth ductwork and limit the length and bends as much as possible, following the instructions that came with the fan.
  • Install a wall or roof cap that closes when the fan is off.
  • Use insulated ductwork in colder climates to prevent condensation on the inside or outside of the duct.

Good luck with your project,


Further Information


  1. Can you vent a bathroom fan into a garage? We recently bought a home and this is what they have done. Is this up to code?

    Thank you.

    • Jess,
      Codes vary from city to city, but regardless of what the code says, it’s not a good idea to vent a bathroom vent fan into a garage. It’s much better to vent the excess moisture all the way outside rather than trapping it in your garage.
      Thank you for your interest!

  2. My building does not allow any modifications to the ceiling. I have a window in the shower. Can I install a vent fan in the window?

  3. Hello, I have just moved into a new property and the vent in the shower installed in the ceiling lets the moisture up into the attic which is insulated. Is this okay?

  4. I have a closed area shower 4 by 4 feet with door, no windows. Can I install regular vent and light or do I need a waterproof one?


  5. Hello, I’m in the process of remodeling our bathroom mainly because of mildew growing everywhere from a poorly installed fan over the toilet. My contractor has hired an electrician that says my fan light combo must be sealed and should not be connected to a GFI. His reasoning is that the moisture from the shower will trip the switch. Which is going against everything I’ve read, but I don’t know codes. Please help! They want to start sheet rock work tomorrow. Should I ask for a second opinion? Is that something you would do with an electrician?

  6. I have a problem with venting a fan in the bathroom because all the walls are concrete and there is no way to exit out on the side of the building insurance reason. The ceiling has a 12-15 inch to the next floor and the walls are only about 2 inch thick. I know that this would cause a problem down line because of the moisture from the vent. Do have a way I can avoid this. No window in bathroom. bathroom center of building weird I know. Thanks ahead of time.

  7. Hi, I need to install a wall mount exhaust fan. The fan says it is suitable for wall depths between 110mm-330mm. Is it possible to install the fan in a wall with a shallower depth?

  8. Hi,
    Can I vent a bathroom’s exhaust fan down into the crawlspace and then outside to the downspout on a gutter?


  9. I have fitted an extractor fan in the ceiling of my bathroom (not yet wired up), and am planning on ducting it outflow a couple of feet through the attic and through the wall of the house. Is there any issue as to where the external vent goes through the outer wall? I specifically want to know if placing it centrally directly above (about 6 bricks up) the bathroom window would be OK, or would it lead in the long term to discolouration of the frame from any water that has condensed and may drip onto the frame? Thanks.

  10. Hello,
    Is the exhaust fan (not a moist resistance) allowed to be right within the shower area? Please let me know.
    Thank you.

  11. I was wondering if it would be alright to run exhaust hose under an addition? The addition has in floor heating and 2 vents on either side of addition

  12. I have a 12×12 bathroom with glass enclosure (about 1 foot from ceiling). My ceiling drywall texture/paint started falling off. I suspect moisture. The vent fan is installed in the middle of the bathroom approx 8 feet from middle of shower. Would you recommend installing another fan (venting into other fan duct work) or changing out the existing one to a higher CPM? Currently a 90 CPM for 12×12 bathroom.

  13. I was wondering, thanks a lot for your kind info,but it is very critical part of a home-ventilation system. can I use 3 inch black ABS pipe to vent fan outside instead of the plastic type flex tubing?

  14. I have moisture causing slight mold issue in the shower. I want to install another exhaust fan in the shower to remove the moisture. The toilet area is next to shower with an existing fan ducted thru roof. Can I tap into this duct with a 45 and vent new fan outdoors? Just starting to plan what to do

  15. Where is the best place to put an exhaust fan in bathroom with only a shower? Also, Which is better to use in shower stall – ceramic or porcelain tile?

  16. I have a bathroom moisture problem. The moisture is damaging the drywall, creating bubbles and peeling on the ceiling as well as mold. there is no ventilation in this bathroom, I don’t know if there ever was. We want to put a vent in but we’re not sure how we can do it. The bathroom is directly under a finished attic. By finished I mean , beautiful wood paneling and flooring that I don’t want to rip up, also, the house is brick. What are our options for getting this moisture out of the house?

  17. Currently my bathroom fan is vented to my attic which is not good. The previous owner taped the end up. I want to vent it to the outside. Can you put in a 90 degree elbow to go up to the roof and attach it to a roof vent?

    • Hi, Jeff,
      Thanks for your 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!

    • Hi, Russell. The exhaust fan’s primary function is to remove moisture and humidity to prevent mold and mildew.
      Removing odors is a secondary function. So, position the exhaust fan near the most moisture, and where the ductwork can be efficiently installed.
      That’s usually near the shower and in the ceiling.
      Happy home improving!


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