Skip to Content

How To Replace & Install A Bathroom Exhaust Fan: A Guide for Beginners

Your bathroom becomes wet and quite hazardous when exhaust fans go up in smoke. But luckily, replacing and installing a bathroom exhaust fan is easier than you think. 

Many homeowners often wonder, how to replace and install a bathroom exhaust fan? 

To replace and install the bathroom exhaust fan, you’ll need to remove the old one. Unscrew the casing and measure the new unit’s area. Make a proper wall hole. After that, set up the junction box and install the exhaust. Connect the junction box from the attic and complete ventilation. 

Anyways, that was the short version of the process. This clearly requires further elaboration on the matter. And I’m more than happy to do that for you.

Keep up with me till the end to learn more about exhaust fan replacement. 

Replacing & Installing A Bathroom Exhaust Fan: A Detailed Process With 16 Steps

Bathroom exhaust fans are an essential part of a household’s overall ventilation. These exhaust fans keep the moisture, odor, and pollution away from our house. 

Replacing a bathroom exhaust fan isn’t an easy task. In fact, it’ll seem really difficult since it involves you being in the attic. 

This is similar to replacing and installing bathroom exhaust fans from start to finish. There are a lot of similarities as you have to do ductwork, ventilation, and installation. 

But no need to worry. To keep it easy, I simplified the process and explained it step by step. 

Step 1: Gather the Pieces Of Equipments

To work on the bathroom exhaust fan, you’ll need a lot of equipment. This is a pretty complex procedure that involves many tools. 

Manage these tools beforehand so that it keeps you focused. It will get pretty annoying if you have to look for something while fixing something. 

Especially because this procedure involves working in the attic. 

Anyways, these are the equipment you’re going to need- 

  • New Exhaust Fan
  • Wire Connectors
  • Duct Insulation
  • 4 Inch Hose Clamps
  • Ventilation Tape
  • Wire Ties
  • Lock Pliers
  • Wire Stripper
  • Flashlight 
  • Headlamp
  • Screwdriver 
  • Voltage Detector
  • Drywall Screw Gun 
  • Box Knife
  • Keyhole Saw

Get these tools as soon as possible and you can start replacing the exhaust fan!

Step 2: Turn Off the Power From Circuit Breaker

The first step is to turn off the power from the circuit breaker. It’s super important as you’ll be working with active wires.

Go to the circuit breaker and look for the switch designated for the bathroom. Identify the switch that’s for the exhaust fan and turn it off. 

This will make the workplace safe for you. Once you’ve turned the circuit off, you can head to the next step. 

Step 3: Remove the Old Exhaust Fan Motor

You can now start working on the removal process. For this, you’ll need a plier and maybe a screwdriver. 

Pull the face plate towards you and it will come off right away. This will expose the fan motor of the old exhaust. Locate the wire that’s connected beside the fan motor.

Once you’ve found the wire, disconnect it. Sometimes it may require some force if it’s old.

After that, use the plier to pull the fan motor. If there are screws, use the screwdriver. 

Step 3: Unscrew the Exhaust Fan Casing

Fan motors aren’t the only component that requires removal. Along with the fan motor, you’ll have to remove the fan casing. 

Fan casings are screwed to the joist. That’s why to remove the fan casing you’ll need to unscrew them first. 

You’ll need a screwdriver and a flashlight for this job. Locate the screws and unscrew them one by one. 

It may take a while. When you’re done, leave the fan casing be. You’ll remove this part at a later step.

Step 4: Measure the New Unit To Get the Total Area

So far you’ve removed the fan motor and unscrewed the fan casing. This now gives you some breathing room to work on the new exhaust fan. 

Get the exhaust fan and unbox it. Use a tape measure or a manual to find out the length and width. 

Compare the exhaust box’s length and width with the wall hole. If the wall hole is smaller, you’ll have to make a new one. 

Speaking of exhaust fans, these are some of my best picks-

Choose whichever exhaust fan you like and get started!

Step 5: Draw & Cut the Area With A Pencil

Take a marker or a pencil and a tape measure to start the process. But before that, decide where exactly you’re going to cut. 

This decision can’t be random because you’ll have to prioritize joists. Make sure the new square is near a joist. Joists act like support so they’re super important. 

Draw the lines properly and make them bold. Make sure the line you have drawn is bigger than the actual length. 

This will create a bigger hole and the box will fit perfectly. Use a keyhole saw and a box knife to cut the drywall. Cutting drywall for plumbing is super easy. 

Step 6: Take Out the Casing

You now have a bigger hole and it’s time to take out the casing. The casing is connected to the power so make sure the connection is off. 

To ensure further safety, use a voltage detector. This will easily detect voltage and prevent potential health risks.

The surrounding wires may still be live so avoid touching them. 

Disconnect the wires from the junction box and you can then take the exhaust out.

Step 7: Install A Support Beam

Bathroom exhaust fans that require two joists as support. If you have that, then you skip this step.

Otherwise, you’ll have to create support by yourself. For this, you’ll need a 2×4 wood piece. Any width between 15 to 20 inches is fine. 

This will help you screw the exhaust box later in the replacement process. 

Take the wood piece and place it parallel to the joist. Take a drywall screw gun and screw it to the drywall. 

Remember to be super careful when drilling nails in the drywall or studs

Step 8: Disconnect the Junction Box & Exhaust Port 

You can now start working on the new exhaust fan model. Take out the device so that you can remove the vent portion.

This will make it easier for you to install the exhaust fan. Locate the screws that are possibly inside of the box. There’s also a wire which needs to be unplugged

Unscrew them and the vent part will come out along with the junction box. 

Step 9: Set up the Wires in the Junction Box

Setting up wires is hard and will need to be done in 4 mini phases. Follow my instructions one by one and you’ll pass this level easily. 

Phase 1: Open Up the Junction Box

The junction box has two knockout holes that can be used to insert wires. Carefully decide which hole you want to use. Take the lid off using a screwdriver. 

Use the screwdriver again to open up the junction box. Pry the cover off and it will expose 3 wires. 

Phase 2: Set Up the Knockout Hole

The lid you just removed will need a setup for the power wire to enter. You’ll need to install a cable connector in this phase. 

Take the power cable connector and unscrew it. Insert it from the outside to the inside. Screw the hex nut from the inside. 

Take the power wire and insert it through the cable connector. After getting enough length, use a screwdriver to tighten the wire. 

Once you’re done, take a channel lock plier to tighten the nut from the inside. This will keep the power wire in one place. 

Phase 3: Connect the wires

You can now connect the junction box wires to the power wires. Match the wire types to connect the wire. 

The hot wire will match hot and the neutral will match with the neutral wire. Connect the ground wire at the end. 

You can use splicing connectors to make this phase super easy. 

When you’re done, close the junction box. Keep the junction box in the hole and keep it far away. Just push it further with your hand.

You’ll access this box later from the attic. 

Step 10: Install the Exhaust Fan Box

It’s time to install the exhaust fan box to the wall hole. Your pain and suffering from looking upward are coming to an end. 

Take the exhaust fan box and insert it into the wall hole. Make sure the box is perfectly aligned with the joist and the support. 

When you’re fully sure, use the screws provided by the manufacturer for screwing. A drywall screw gun is recommended for this. 

Step 11: Go to Attic & Connect Junction Box

Your work in the bathroom is done and the rest is in the attic. Take a break if you want to and then go to the attic. 

You’ll need a headlamp for this step. Find the box and then install the junction box. If the screws are from the inside, you’ll have to come back once to screw it. 

Step 12: Connect the Insulated Vent Duct

This is the final part of the installation. The insulated vent duct has to be connected to the exhaust port. 

Take the insulated vent duct and plan accordingly. Connect the vent duct to the port and tighten it with a 4-inch hose clamp. You’ll also need a screwdriver to secure it. 

After you’re done, go to the exhaust port that connects to your roof. Take the ventilation tapes and wrap them around the connection. 

After that, take another hose clamp and tighten the connection. Use another round of vent tapes to wrap the hose clamp for further protection. 

This will make the whole connection as strong as possible. Other than that, make sure all the wirings are done correctly. 

Wiring around the studs inside drywall can be tricky but it’s pretty easy. You can use the zip ties to make sure the connections are firm. 

They prove to be extremely helpful in the ductwork. When you’re done, go to the circuit breaker and turn the power on. 

Switch on the power and check the ventilation. 


Can you replace a bathroom exhaust fan without going into the attic?

Yes, it’s possible to replace a bathroom exhaust fan without going to the attic. In this case, the screws have to be removed from the inside. But the attic access is still the solution. Because you can easily make the ventilation system in the attic. It also gives you more freedom while installing.

Can you replace just the fan on the bathroom exhaust fan?

Yes, it’s possible to replace just the fan on the bathroom exhaust fan. You’ll need a room-side install type of fan models. Simply remove the old fan, do the wiring and ductwork and you’re done. But replacing the entire unit is the best thing to do. Because most top products come as a full unit. 

How often should a bathroom fan be replaced?

A bathroom exhaust fan should be changed or replaced every 10 years or so. This depends on the quality of the fan and the overall usage. Cleaning and maintaining the exhaust fans once a year can ensure a long-term life. But due to technology getting better, it’s worth buying the latest models. 

Take Away

That was everything I could explain on how to replace and install bathroom exhaust fans. I hope that my technique was enough to give you some insights about the job. 

If the procedure seems too complex, don’t worry. In fact, it’s one of the toughest DIY works for homeowners. Simply give a call to your nearest services and explain the situation. 

Finally, have a nice day!