How to Install a Bathroom Fan Where You Need One

Before installing an exhaust fan, use a pencil to mark the area you will cut away. You'll want to position your new exhaust fan on a stud in the wall or ceiling, so make sure you mark it on top of at least one.

If you happen to be replacing an old fan or relocating one, you'll need to shut off the power source to the bathroom before beginning. Use a circuit tester to ensure it's off before starting.

You'll be working on both sides of the ceiling, so head into your attic and clear away any boxes or items that may get in the way. You might also want to set up a light source close to the area if your attic isn't well lit. Before you cut, have reference points for all four corners of the new fan, and mark these with tape or a pencil.

For easy cleanup, consider putting a sheet of plastic or tarp below your work area to catch debris from the ceiling. Using a drywall saw or reciprocating saw, cut away the area to make space for the fan. Gently remove the piece once you cut it out and set it aside or in the trash.

Use screws to connect the bathroom exhaust fan to the joist using a power drill and screws. Ensure the fan receptacle lines up neatly with the edges of the ceiling. Don't plug in your device just yet.

Install your bathroom vent through your roof. Venting the fan into your attic is not a good idea, as it creates an ideal environment for mold or mildew in your air ducts and other areas of your home, which could cause big problems later.

Always practice good roof and ladder safety, such as having someone spot you from the bottom of the ladder when you climb. If this step is out of your wheelhouse, especially since there’s the risk of injury when working on the roof or climbing a ladder, consider hiring a pro.

Measure the hole size needed to get the vent and tailpipe through the attic or side of your home. Mark a circle that's an adequate size for the opening of the vent and tailpipe on the ceiling of the bathroom and the section where you will funnel the pipe outside the home before making any cuts.

Find a reference point on the top of the roof before cutting. Start by drilling a single hole. Peel back the shingles in that area (instead of guessing from the inside and possibly cutting into shingles), then mark the section and make your cuts using a reciprocating saw from inside the attic. 

After installing the vent, you'll need to lay the shingles back down around the edges of the hole.

Pull the roof vent through the hole you've created. Once in place, spread all-weather outdoor caulk around the edges and secure the vent with roof nails if your model has space.

Replace the roof shingles (you'll likely need to cut them to fit around the vent) around the edges. Use roofing cement to seal.

Turn off power to the fan if you haven’t yet, and use a circuit tester before starting this step. If you feel uncomfortable doing this, ask a local electrician for assistance. Don’t take any chances regarding the safety of yourself and your home. 

Remove the fan motor from the receptacle. Run a cable from the fan to the switch if wiring isn't present. Carefully read instructions from your bathroom fan on how to wire the device to the new cable. Most homeowners want their bathroom fan on a separate switch from the lights, which might take additional steps, depending on your existing wiring.

Put the fan motor back in the receptacle and secure it, as per the instructions that came with your unit. At this point, you can also plug the fan in.

Attach the grille to the open section in your bathroom with screws (or clips). 

Turn the circuit back on to power the bathroom. Turn the fan switch on to test it. If it doesn't work and you need to troubleshoot, make sure you turn the power off to the circuit before proceeding. Use a circuit tester to be safe before beginning.