How to Install a Bathroom Exhaust Ceiling Fan & Light

Updated February 21, 2017

A bathroom ceiling fan is an important piece of equipment when it comes to keeping your bathroom clean. The fan removes unpleasant bathroom odours, as well as moisture that can cause mould and mildew to grow inside the bathroom. Some bathroom ceiling fans have a built-in light, which can improve the lighting in your bathroom. When you install a bathroom ceiling fan, vent the fan outside your home and not to the attic, as you just wind up dumping the moisture there.

Drill a hole into the ceiling where you are installing the fan with a 3/8-inch spade bit. This acts as a reference point when you are in the attic.

Go into the attic where the hole comes through and remove the insulation from the surrounding area. Measure the fan's housing and place it near the hole between two ceiling joists, then return to the bathroom.

Measure the inside of the fan's intake port. Mark the outline of the intake port on the ceiling with a framing square.

Cut a hole in the ceiling along the outline of the intake port. Make the cut with a reciprocating saw, and wear safety goggles and a mask.

Go back into the attic. Connect a 90-degree sheet metal duct elbow to the outlet port on the side of the vent housing with the elbow pointing straight up. Wrap duct tape around the joint.

Remove the knockout hole on the side of the vent housing. This is the recessed hole which the electrical cable will run through. Attach the cable connector to the knockout hole.

Slide the metal brackets into the tabs on the sides of the fan and centre the fan on the hole in the ceiling. The brackets are included with the fan.

Extend the brackets out from the fan until they come into contact with the joists. Attach them to the joists with 1 1/2-inch stainless steel drywall screws.

Connect the flexible duct to the 90-degree elbow with duct tape. Handle the flexible duct carefully so you don't tear it.

Run an electrical cable between your home's main electrical box and the fan inside the attic.

Insert the electrical cable through the cable connector. Tighten the connector screw.

Choose a location for the exterior vent on the exterior wall of the attic no more than 6 feet away from the fan. Pick a spot between two wall studs located near an object, like a window, which can be a reference point on both sides of the wall.

Measure the distance between the location where you are installing the exterior vent and the reference point.

Go outside to the wall where you are installing the vent. Climb a ladder and mark the spot on the wall where you are installing the vent, using the measurements from the reference point. Remember to reverse the direction when you are outside -- if the reference point was to the left inside the attic, it will be on the right when you're outside.

Drill a hole with a 4-inch hole saw. Hold the wall cap against the wall to see if it fits flat against the wall. If there is a gap, you need to install a rubber gasket.

Go back into the attic. Stretch the flexible duct to the hole in the exterior wall, again handling the duct with care.

Connect the 12-inch long connector duct to the flexible duct with duct tape, then slide the connector duct through the hole in the wall. Go back outside to the hole.

Apply a thick bead of silicone adhesive to the rubber gasket and press it into the back side of the wall cap, if needed.

Slide the wall cap onto the connector duct. Wrap duct tape around the joint to secure it.

Apply a thick bead of silicone adhesive to the wall around the hole. Press the wall cap tightly against the wall and screw it into the wall with four 1 1/2-inch stainless steel screws.

Hire an electrician to connect the electrical cable to your home's electrical box. Not only is this extremely dangerous if you don't know how to do it properly, many municipalities require that a certified professional complete this work.


Wear safety goggles when sawing or drilling into the wall and ceiling. Wear safety goggles, gloves and a mask when handling the fibreglass insulation.

Things You'll Need

  • Drill
  • 3/8-inch spade bit
  • Measuring tape
  • Safety goggles
  • Gloves
  • Mask
  • Framing square
  • Reciprocating saw
  • 90-degree sheet metal duct elbow
  • Duct tape
  • Cable connector
  • 1 1/2-inch stainless steel drywall screws
  • Flexible duct
  • Electrical cable
  • Screwdriver
  • Ladder
  • 4-inch hole saw
  • Wall cap kit
  • 12-inch long connector duct
  • Foam rubber gasket
  • Silicone adhesive
  • 1 1/2-inch stainless-steel screws
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About the Author

Carson Barrett began writing professionally in 2009. He has been published on various websites. Barrett is currently attending Bucks County Community College, pursuing a Bachelor of Arts in sports management.