How to Install a Bathroom Exhaust Fan

Remove the motor from the housing. If the motor is held in place with screws, remove the screws and disconnect the motor from the wiring.

Fan manufacturers have different methods for securing housing.

• If your fan is held in place by mounting screws secured to a ceiling joist, remove the screws attached to the joist.
• If your fan is held in place with metal brackets secured to the ceiling joists, and you have access to the fan through an attic, remove the screws or nails holding the brackets to the joists. Then follow Option 1 below.
• If you don’t have access to the fan through the attic, you’ll have to cut the brackets from below. Use an oscillating saw or reciprocating saw to carefully cut the brackets. Avoid cutting electrical wires and expect to touch up the ceiling drywall with spackling later. Then follow Option 2 below.

Disconnect the electrical connections. Move the housing around in the hole so you can access the electrical and duct. Disconnect any additional electrical and pull the house wire out of the fan housing. Remove the exhaust duct from the fan too. Then remove the fan housing from the ceiling.

If the hole is too big, you’ll need to patch the ceiling. Cut a piece of drywall to make the ceiling hole the right size for your fan. Attach the drywall filler to a larger piece of wood; set it in the hole and drive screws through the ceiling into the wood. The patched areas can be repaired with spackling compound later.

Remove the wiring cover on the housing, and remove the knockout plug with a screwdriver.

Pull the house wires through the clamp and tighten the screws. Using quick connector or wire connectors, connect the fan wires to the house wires, matching the colors. Green is the ground and connects to the green or bare copper house wire. White is neutral and connects to the white house wire. Black is hot and connects to the black house wire.

To use quick connectors, just push the bare wire into the connector. To use traditional wire connectors, hold the two wire ends together and twist the connector clockwise.

Push the wires into the housing. Secure the wiring cover to the housing with screws.

Connect the duct. Secure a 4-inch duct to the duct connector with HVAC tape or a clamp. The duct should vent to the outside. If you don’t have an attic duct, see the installation steps later in these instructions.

Turn on the power and check that the fan works. Some fans are extremely quiet, so listen carefully.

Install the grille by squeezing the springs into the slots and pushing the cover toward the fan. Touch up the ceiling with spackling compound and ceiling paint.

If the hole is too big, you’ll need to patch the ceiling. Cut a piece of drywall to make the ceiling hole the right size for your fan. Attach the drywall filler to a larger piece of wood; set it in the hole and drive screws through the ceiling into the wood. The patched areas can be repaired with spackling compound later.

Also make sure the fan can be mounted to at least one ceiling joist. If your old fan wasn’t attached to a joist and there's a space between the joist and the ceiling hole, attach lumber to the joist and build it out next to the hole so the fan can be screwed to solid wood.

On the side of the hole opposite the joist, attach a piece of 1x lumber inside the hole. Just drive screws through the ceiling. Now you’ll have two sides to secure the fan housing.

Secure the duct connector to the duct in the ceiling with HVAC tape or a clamp. Be sure to install the duct in the position specified by the instructions so the housing will line up correctly. The duct should vent to the outside. Then use a screw to attach the duct connector to the edge of the hole so it'll line up with the exhaust on the fan housing. Some manufacturers suggest securing the duct connector to the edge of the ceiling hole. Determine where it'll attach the fan housing and secure it to the ceiling with a screw.

Remove the wiring cover on the housing, and remove the knockout plug with a screwdriver.

Secure a cable clamp to the hole on the wiring cover.

Pull the house wires through the clamp and tighten the screws. Using quick connectors or wire connectors, connect the fan wires to the house wires matching the colors. Green is the ground and connects to the green or bare copper house wire. White is neutral and connects to the white house wire. Black is hot and connects to the black house wire.

To use quick connectors, just push the bare wire into the connector. To use traditional wire connectors, hold the two wire ends together and twist the connector clockwise. 

Push the wires into the housing and secure the wiring cover to the housing with screws.

Insert the fan into the ceiling hole, lining up the exhaust with the duct connector. Secure the fan to the wood supports with screws through the mounting flange.

Turn on the power and check that the fan works. Some fans are extremely quiet, so listen carefully.

Install the grille by squeezing the springs into the slots and pushing the cover toward the fan. Touch up the ceiling with spackling compound and ceiling paint.

Hold the other end of the flexible duct against your installation spot on the underside of the roof between two rafters. Cut the duct to length with scissors or a utility knife. The wire of the duct can be cut with side cutters.

Drill a hole through the roof with a small drill bit. Leave the bit in the roof so you can find it from the outside. From the outside, locate the drill bit. Use a 5-inch hole saw to cut a hole through the shingles and roof. It might take some time to cut through the roof.

Attach the duct connector to the roof vent cap. Insert the connector in the hole, straighten the cap and trace the outline on the shingles. Remove the cap.

Cut away the shingles just inside the outline following the manufacturer’s directions. Cutting inside the outline will leave a little bit of overlap of the roof cap.

Apply roof cement around the hole and insert the roof cap. It should slide under the shingles. Even it up with the shingles and secure with roofing nails. Apply roof cement where the shingles overlap the roof cap flange and cover any nail holes.

From the inside, attach the flexible duct to the duct connector with HVAC tape or a clamp. Pull the insulation over the connection.