How to Install a Bathroom Fan

Have you bought a bathroom fan and want to install it yourself? Let's go through the steps and see if it's something you want to tackle.

 

Steps

 

Determine where you want to install the fan. If this is a remodel and you are replacing an existing unit, this is pretty easy. If this is a new installation you will typically need to install the fan in a location where it can be attached to a ceiling joist, which you can locate using a stud sensor or any other method you prefer.

Cut a hole in the ceiling larger than the finished opening (unless you have access from above) in order to get the fan housing into the ceiling and to attach it to the joist for support. A good method to do this is to use a rotary cutting tool, like a rotozip, or a drywall saw.
Turn off power at the breaker and be careful not to cut any electrical wiring if this is a remodel). Be sure to wear goggles and a dust mask!

Instructions for Replacing Existing Fan
1

Disconnect the electrical connections from the existing fan and remove the housing through the previously cut hole. Be careful as the housing is attached to the vent duct and you will want to re-use this.
2

Prepare the new fan for installation by verifying the exhaust duct is the same size as the exhaust on the housing. Determine what kind of electrical cable is running to the fan and put the appropriate cable clamp in the electrical housing knockout.
3

Attach the new fan to the ceiling joist, connect the exhaust duct, and run the electrical cable through the previously installed clamp into the housing.
4

Connect all the electrical cable to their approriate wires/terminals and make sure the fan unit is properly grounded.
5

Turn on power at the breaker and test the fan to ensure proper operation. Once tested, turn off power until install complete.
6

Skip New Installation instructions and proceed to "Common Instructions"

Instructions for New Installation
1

Recognize that a new installation can be quite complex and might be best undertaken by a pro. However, it can be easily accomplished if it is for a bathroom where you have access from above and a clear path to run exhaust duct.
2

Find power for the fan. You will need to run one or more switched circuits to the fan location from your switch location. A single circuit is typically all that is needed for the fan, light and heat unit, if equipped. You will need to refer to another reference source for instructions on accomlishing this.
3

Find an exhaust duct, which is typically vented to the outside through the roof or through the side of the house. Again, you will need to refer to another source for these instructions.
4

Know that you can now install the fan. Prepare it for installation by installing the appropriate cable clamp in the electrical housing knockout(s) for the cable that was run to the unit.
5

Attach the fan housing to the ceiling joist, attach the exhaust duct and connect up the electrical to the appropriate wires/terminals.
6

Test the fan for proper operation by turning on power at the breaker and testing the switch(es). Once operation is verified, turn off power until install complete.

Common Instructions
1

Know that now we have a fan attached to the joist and all hooked up, with a nice gaping hole in the ceiling surrounding it. We need to fix this hole...
2

Do this by cutting back the ceiling material (typically greenboard or drywall) so that you have a square or rectangle that has at least 1/2 of the ceiling joist edges on either side of the fan exposed to screw a new piece to.
3

Cut a new piece of drywall/greenboard to fit in the enlarged hole and mark the location of the housing flange on the backside of the piece to cut out the opening for the fan. (A simple method of doing this is to use an old lipstick to run on the edge of the fan housing. When you push the drywall against it, it leave a nice cut line.)
4

Cut out the fan opening and hold up the piece to test the fit. Adjust as necessary.
5

Install the drywall using 1 5/8" drywall screws along the ceiling joists and either drywall clips and screws or backer boards and screws along the unsupported edges.
6

Tape and mud the joints (you will have to learn to do that bit elsewhere). Now, install any bulbs in the fan unit, put on the cover and turn on the power at the breaker.

 

Tips
Buy the bathroom fan from a reputable retailer.
Be sure to get a fan that moves enough air for the size of bathroom you are venting.
Get a fan as quiet as you can afford, you will be happier in the end.
Use a step-ladder for high ceilings.
If you aren't comfortable doing electric work, drywall or running the ducts, hire someone to do it for you. You will end up saving time and frustration and it will be worth the money.

 Warnings
Turn off the electricity supply before installing the appliance.
If using a ladder, have someone support it whilst you are installing the fan.
Make sure you follow all instructions completely.
If you know nothing about electricty, it would be better to hire someone that knows about wiring. The wrong wire connected to the right or wrong wire can cause a lot of damage which could includ a fire or killing you.
If using power tools for any portion of this project, be sure you are familiar with their operation.

Things You'll Need
Bathroom fan.
Drywall saw or rotary saw
Electrical supplies (wire, boxes, housing clamps, etc.)
Exhaust Duct (for new installs)
Razor Knife
Greenboard or drywall
Drywall tape
Joint Compound
Light bulbs for light/bathroom fan.
Ladder
Power Cut-Off.: