How To Install A Bathroom Fan? Step-By-Step Guide

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Last Updated on April 28, 2023 by acechapman

Bathroom fans are an essential component of any well-ventilated bathroom. They help to remove excess moisture and prevent mold and mildew from forming. Installing a bathroom fan can be a relatively easy task, even for those with limited DIY experience. In this comprehensive guide, we’ll walk you through everything you need to know about how to install a bathroom fan, from selecting the right fan to mounting it properly.

Tools and Materials You’ll Need

Before starting to install the bathroom fan, you’ll need to gather all the necessary tools and materials. Here’s a list of what you’ll need:


  • Drill
  • Jigsaw
  • Pliers
  • Screwdriver
  • Pencil
  • Measuring tape
  • Utility knife


  • Bathroom fan kit (this will include the fan housing, fan unit, and vent pipe)
  • Wire connectors
  • Screws
  • Duct tape
  • Electrical cable
  • Electrical connector
well-ventilated bathroom

Choosing the Right Fan

Before you can start the installation process, you need to choose the right fan for your bathroom. When choosing a fan, you need to consider a few things, such as the size of your bathroom and the level of humidity. Here are some factors to consider:

Bathroom Size

The size of your bathroom will determine the size of the fan you need. You’ll need to calculate the square footage of your bathroom and choose a fan with the appropriate CFM (cubic feet per minute) rating. As a general rule of thumb, you’ll need a fan that can move at least 1 cubic foot of air per minute for every square foot of bathroom space.

Humidity Level

If your bathroom tends to be very humid, you may want to consider a fan with a higher CFM rating. A fan with a higher CFM rating will be able to remove moisture from the air more quickly and efficiently.

Noise Level

Bathroom fans can be noisy, so you may want to choose a fan with a low sone rating. The sone rating measures the level of noise a fan produces, with lower numbers indicating quieter fans.

Types Of Bathroom Fans To Consider

Here are some types of bathroom fans to consider:

  1. Ceiling-mounted fans: These fans are installed into the ceiling and are a popular choice for bathrooms.
  2. Wall-mounted fans: These fans are mounted on the wall, and they are a good option if you have limited ceiling space or if you want to install the bathroom fan directly over the shower or bathtub.
  3. Inline fans: These fans are installed in the attic or in the ductwork, and they are ideal for large bathrooms or if you need to vent the air a long distance.
  4. Combination fans: These fans have a built-in light or heater, and they are a good option if you need to add more functionality to your bathroom.
  5. Smart fans: These fans come with built-in sensors that detect humidity levels and automatically turn on when needed. They are a great option if you want to save energy and keep your bathroom dry.
  6. Quiet fans: These fans are designed to operate quietly, which makes them a good option if you are sensitive to noise or if you want to enjoy a relaxing bath without any distractions.
installing a bathroom fan

How To Install A Bathroom Fan

Once you’ve chosen the right fan, it’s time to start the installation process.

Turn Off Power

Before you start working on the electrical components of the fan, you need to turn off the power to the bathroom. Locate the circuit breaker box and switch off the power to the bathroom. Test the power to make sure it’s off by turning on the light switch.

Locate the Position of the Fan

The next step is to locate the position of the fan. You want to install the bathroom fan in the ceiling, as close to the exterior wall as possible. This will ensure that the fan can effectively pull moisture and steam out of the bathroom. It’s also important to avoid installing the fan directly above the shower, as this can lead to electrical hazards.

To locate the position of the fan, measure the distance between the walls of the bathroom and mark the center point. From there, measure the distance between the center point and the exterior wall. This will give you the position of the fan.

Cut the Hole

Once you’ve located the position of the fan, it’s time to cut the hole for the fan housing. Use a jigsaw to cut the hole in the ceiling. Make sure the hole is the same size as the fan housing. If the hole is too small, you won’t be able to install the bathroom fan housing. If the hole is too large, the fan housing won’t fit properly.

Install the Fan Housing

Once you’ve cut the hole, it’s time to install the bathroom fan housing. Begin by removing the cover from the housing. Then, place the housing into the hole in the ceiling, making sure that it’s level. Use a pencil to mark the location of the screw holes.

Next, drill pilot holes for the screws using a drill bit that’s slightly smaller than the screws you’ll be using. This will help prevent the ceiling from splitting when you screw in the screws. Then, insert the screws into the pilot holes and tighten them until the fan housing is secure.

Connect the Wiring

With the fan housing in place, it’s time to connect the wiring. Start by turning off the power to the bathroom. This can be done by turning off the circuit breaker that controls the bathroom.

Next, remove the wiring cover from the fan housing. Then, connect the fan’s wiring to the wiring in the ceiling. Use wire connectors to make the connections, and make sure that the connections are tight and secure.

If you’re not comfortable with wiring, it’s always a good idea to hire a professional electrician to do the wiring for you.

Install the Fan Unit

With the wiring connected, it’s time to install the bathroom fan unit. Begin by removing the fan unit from the packaging. Then, insert the fan unit into the fan housing, making sure that it’s securely in place.

Next, connect the ductwork to the fan unit. The ductwork should run from the fan unit to the exterior of the house. Use duct tape or clamps to make the connections, and make sure that they’re tight and secure.


Installing a bathroom fan is a great way to reduce excess moisture, prevent mold and mildew, eliminate unpleasant odors, and improve ventilation in your bathroom. With the right tools and materials, the installation process can be relatively simple and straightforward.

By following the steps outlined in this blog post, you’ll be able to install a bathroom fan that will improve the air quality in your bathroom and help keep your home healthy and comfortable. Remember to always prioritize safety when working with power tools and electrical wiring, and don’t hesitate to seek professional help if you’re not comfortable with any aspect of the installation process.

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