Back to Articles

Broan XB110L

Bath Fan Installation: An Overview


Installing a bath fan is probably not the easiest of tasks for a first time home project, but it can be a DIY project if you would like to save money on installation. For example, if you’ve purchased a new home and the home has a loud, noisy or inefficient bathroom fan, you may prefer to replace it with a quiet bathroom fan that also provides light and heat. If you do choose to install the bathroom fan on your own, the process of installing a new bath fan will be easier as steps 1-4 below will already be completed.

On the other hand, if you’re installing a bathroom fan for the first time, be sure to read all of the instructions that come with your fan and then follow these guidelines.

1. Cutting The Hole

If you have an attic, you’ll want to position the fan flush with a joist, and outline the fan using a pencil or marker. You’ll then cut the appropriate size space using a small saw. If you don’t have an attic, simply use a stud finder to determine the location of the joist. Pencil the outline of the fan from inside the bathroom and cut out the space.

2. Attaching Your Bathroom Fan

Using the joist as an anchor, attach the fan to it with screws. If there is insulation present, you’ll need to cut  or push it back so that there is at least six inches between the fan and the existing insulation. Use a 2x4 to sit between joists for added safety, ensuring the insulation is away from the fan.

3. Cut Your Roof Hole

Using the roof cap and tailpipe as a guide, draw an appropriate sized circle on the interior of the roof. You’ll need to then drill a small hole so that you can saw out the circle for the bath fan roof cap.

4. Remove Shingles

If you have shingles on your roof those, near the roof hole will need to be removed,

5. Attach The Roof Cap

Affix the roof cap by putting the lower part of the roof cap flange on the shingles. The top part needs to be under the shingles. Use a roof cement to secure the flange, and reattach shingles on the sides of the roof cap. Secure with roofing nails, and further secure the nails with roofing cement.

6. Attach Ductwork

Attach the flexible duct to the roof cap and the fan, using clamps. For extra security, cover all of the joints with duct tape.

7. Connect Wiring

Follow the instructions from the manufacturer on how to connect the wiring. If there is no wiring, you’ll need to run a cable to the fan.

8. Connect Wiring to Switch

Connect the wires according to the manufacturer’s instructions. You may be required to splice white wires and connect using wire connectors.

It is advisable that you have someone to help you install your first bath fan. The added assistance will help reduce time, and ensure that you have someone double checking your work, and helping you to follow instructions.