How to Replace or Install an Easy Install Bath Fan

As you figure out how to replace a bathroom fan, get your tools and materials together.

For this project, you will need:

• An easy-install bathroom fan model
• Ladder
• Measuring tape
• Circuit tester
• Screwdriver
• Drill
• Drill bits
• Jab saw
• Duct tape
• Drywall screws
• Cable clamp connector
• Wire connectors
• Spackling compound
• Paint

If you’re replacing an old bathroom exhaust fan, opt for a new fan that’s the same size as the old one. This will reduce the amount of cutting or patching you’ll need to do on the ceiling.
The airflow (measured by cubic feet per minute, or CFM) and noise level (measured in sones) of the fan are important considerations when choosing the right fan for your bathroom.

• Calculate the CFM for your bathroom: Measure the length, width and height of the bathroom. Use the formula Length x Width x Height x (.13) = CFM. Round the result up to the nearest 10.
• Generally, a 50 CFM fan will work for a small bathroom. Larger bathrooms will need a fan with at least 100 CFM.
• A fan with a sone measurement of 2 is considered quiet. The higher the sones, the louder the fan.

When you are replacing a bathroom exhaust fan, you'll start the project by removing the old fan.

• Before you begin, turn off the electrical breaker to the bathroom fan.
• Remove the existing fan cover. Next, use a circuit tester to ensure the power is off.

• Use a screwdriver to remove the screws that attach the motor to the housing.
• Remove the motor from the housing, then disconnect the wiring from the motor.
• Remove the housing mounting screws with a screwdriver. If the fan housing is attached with mounting brackets, carefully cut the brackets with a reciprocating saw or oscillating saw. Avoid cutting through any wiring or ductwork.

How to replace bathroom fan wiring begins by disconnecting all electrical wires and the exhaust duct from the fan. Remove the fan housing from the ceiling. You may need to rotate the housing in the hole to access the wiring and duct.

If you’re replacing an existing fan of a different size, you may need to make the hole in the ceiling bigger or smaller.

• Check the size of the hole by holding the new fan housing up to the existing hole.
• If you need a bigger hole, trace around the new housing on the ceiling. Then, use a jab saw to cut the hole larger.
• If the existing hole is too large, cut a piece of drywall to reduce the size of the opening. Cut a piece of 1- x 4-foot lumber that is 4 inches longer than the long side of the patch.
• Place the 1x4 in the opening so that part of it is above the existing ceiling and part is in the opening. Attach it by screwing through the ceiling and then attach the patch to the wood with screws. The screw holes and the seam will need to be mudded and taped if the new fan’s face doesn’t cover them.

• The new fan housing will have a duct adapter with a gravity operated damper in it. Ensure that the damper is installed on the housing properly.
• Put the housing into the ceiling by turning it sideways and feeding it through the opening.
• Slip the existing duct over the adapter and affix with foil duct tape.
• Align the fan housing with the opening and attach to the ceiling, usually with bend-down tabs or screws, and to the joist with screws. Refer to the manufacturer’s instructions for specific details on how to attach the new fan.

Here’s how to connect the wiring to your new bathroom exhaust fan:

• Remove the wiring cover from the housing. Use a screwdriver to remove the knockout plug.
• Secure a cable clamp on the wiring cover hole.
• Pull the house wires through the cable clamp and tighten the screws.
• Connect the house wires to the fan wires by matching wire colors.
• Connect the green ground wire to the green or bare copper house wire.
• Connect the neutral white wire to the white house wire.
• Connect the “hot” black wires, which carry the electricity from the breaker to the fan.
• Place the wires into the housing, then screw the wiring cover back on the housing.

Tip: Use quick connectors to easily connect the wires.

Install the fan into the housing. Be sure that the fan’s outlet is aligned with the duct.

Secure the bathroom exhaust fan with screws that were provided in the fan kit.

Turn the power back on, and make sure the new fan works. If so, slide and secure the cover into place.

Once the new bathroom exhaust fan is in place, touch up the ceiling with spackling compound. Paint the compound to match your ceiling.