How to Install a Bathroom Fan

Bathroom fans are a highly necessary component for any bathroom. They are essential when it comes to eliminating unpleasant odours, minimising moisture that can promote the breeding of mould and mildew and keeping your bathroom a hygienic, tranquil environment.

The benefits of a bathroom extractor fan also include the fact that you can prevent or minimise the risk of peeling wallpaper, cracked paint and warping. The fortunate thing is that you don’t have to be a DIY genius to attempt this project. A basic knowledge of electricity and plumbing will serve you well.

To get started

  • Establish what your cubic feet per minute is. Smaller bathrooms have a lower threshold whilst larger bathrooms have a higher threshold. Any fan you purchase will advise the cubic feet per minute on the box. To see if this is compatible with your bathroom, a basic mathematical equation is suitable. Simply multiply the length, width and height of your bathroom to establish its CFM.


  • A fan’s sound rating is measured in sones, varying from very quiet to loud. Depending on your sensitivity to noise, this is something you will need to consider. Sones vary between the quieter end of the scale (0.5) to louder (6).


  • Think about where you want your fan to be positioned. If your bathroom is comprised of a shower enclosure and toilet, it is ideal to place it somewhere centrally between the two. Larger bathrooms may benefit from more than fan for optimum ventilation.


To install

  • Fans are typically positioned via the attic between two joints so you’ll need to consider how the practicality of this impacts on its aesthetic placement in your bathroom. If you are replacing older fans, feel free to use the same spot, as long as you were happy with this placement.


  • Prepare your tools! It’s better to have them all to hand at the beginning of the project. You’ll need a screwdriver, assortment of pliers, power drill, jigsaw, duct tape, a vent cap, screws, caulk, a stepladder, goggles and wire nuts.


  • Once your equipment is ready, mark and drill a reference hole into the ceiling. This hole should mark where you want your fan to go. Go to your attic and seek out your reference hole. Measure the area to check your fan will fit and clear away any items or clutter obscuring the project. Also make sure that the placement is between two joists.


  • Cut an appropriate sized hole into your ceiling using your jigsaw based on the measurement of your fans intake port. Mark this exact size on your ceiling.


  • Place the fan into its new position. Just prior to this, make sure you’ve attached a 90 degree duct elbow to the outlet securing with duct tape. You can then insert your cable connector through the knockout hole and then secure the connecting metal brackets. You can then insert your fan fully into its hole.


  • Firmly secure your fan in place by screwing it into position to each joist.


  • Find a suitable exit for your duct pipe so that your bathroom remains well ventilated and connected to the outside. Try to choose the shortest, straightest, easiest route available.


  • Secure the vent cap in place


  • Turn off the power and wire your connections to the housing unit. This process can be a little complicated so have your instructions to hand. Pull out the fan wires and strip between 5-8 inches back from the fan and electric cables. Twist the wires together (white with white and red with black or black with black) and add your connectors. Secure the bare copper wire to your green grounding clip and secure in place.


  • As the wiring process is tricky, it is essential if you are not confident that you have done this correctly, that you call in the expertise of an electrician to either do it for you or check that you have done it correctly.