How to Replace a Bathroom Exhaust Vent Fan

Bathroom exhaust vent fans are needed to remove excess humidity that can lead to mold or mildew and cause damage to your walls or ceiling. Unlike older vent fans, new models are much quieter and more efficient. Here’s how to replace an existing vent fan with a new one:

  • When choosing a vent fan for your bathroom, look for a model that is quiet (1.5 sones or less) and moves enough cubic feet per minute (CFM) of air as discussed in sizing a bathroom vent fan.
  • Cover the bathroom floor to protect it from scratches.
  • Turn off the circuit breaker that controls the bathroom vent fan.
  • Remove the cover on the bathroom vent fan.
  • Disconnect the wiring and remove the fan motor from the housing.
  • Disconnect the vent pipe from the fan housing.
  • Remove the vent fan housing.
  • If needed, adjust the existing hole in the ceiling to fit the new vent fan housing.
  • Attach the vent fan housing to the ceiling joists.
  • Connect the electrical wires to the vent fan housing.
  • Connect the vent pipe to the fan housing.
  • Attach the vent fan motor and electrical wires to the housing.
  • Snap the cover or trim on the vent fan.
  • Turn on the circuit breaker and test the vent fan to make sure it’s working properly.

Watch this video to find out more.

Further Information


  1. Can a bathroom exhaust fan be vented into a plumbing stack that runs through the roof or will that cause some sort of down draft problem?
    Steve Johnson

  2. my home was built in 1947 and doesn’t have a fan nor there isn’t room in the ceiling. am I able to get one installed on a vertical exterior wall? I am a disabled veteran that could really use your help with that and some other things.
    possible a future show (hint hint)

    leo kelly

  3. Ive had a exhaust fan installed 2 yrs ago and realize I would have preferred a fan with a heated option , is this as easy as switching it out or is the electrical set up going to be an issue.

  4. I have a new home I moved into 5 years ago and just realized that my bathroom exhaust fan is not vented in attic to the outside of my home. What do I need to do to fix this problem? I am smelling an odor of mildrew in attic. Thank you
    Dawn Frommeyer Adams

  5. I have a cathedral ceiling in renovated bathroom and the shower is open to the ceiling and it is a 110 CFM but it is not taking the Moisture out of the room. The exhaust fan is vented in the shower but uses in the older part of the bathroom as the route outside. ( a run of 9 feet horizontally and then up through the older roof to the outside vent approximately 10 feet.
    My question is can I exhaust the fan in the shower stall right through the cathedral ceiling or the wall of the addition. The addition is Stucco. Please advise. Thank you for your assistance in the matter.

    • Hi, Kathleen!
      Danny says, “Any exhaust fan in your house works much better with the shortest possible vent to the outside. If the existing venting can be changed or altered to allow that, it would definitely work much better to exhaust the hot moist air.
      “Another consideration is that with a cathedral, or vaulted, ceiling, you’re dealing with a lot of cubic feet instead of square footage. A larger exhaust fan may also be needed and I would suggest you check the calculators available at ( Good luck with your project!”

  6. What are your suggestions for installing when you do not have access to the attic? Or if on the first floor in a two story home – again no access like the guy working from the top.

    Thanks, Jeff S.

    • Hi, Jeff,
      Danny says, “A good solution there would be to install a wall-mounted exhaust fan.
      Thanks for your question!”

  7. My vent fan blows inside the bathroom> does not vent outside the duct leading outside! The condensation stays in the bathroom,when I turn the fan on! Do I need to buy another one? Is it on backwards?


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