How to Fit an Extractor Fan in Your Bathroom?

The steps how to fit an extractor fan demand more knowledge and skills from a DIY enthusiast. These include experience in handling household electrical wiring, which can be a dangerous job. This is a basic guide for fitting an extractor fan in your kitchen, bathroom, or laundry room.


First Read: Safety tips for DIY projects

An extractor fan removes the odor, smoke and moisture in the area. You can buy it in two main types:

  • An axial fan can be mounted on a window or an exterior wall. It works by transporting air over shorter distances and, thus, removing the undesirable aspects.
  • A centrifugal fan moves the air over longer distances. It is usually mounted into ceilings.

You can ask the extractor fan salesman about the pros and cons of each type. You may choose a centrifugal fan because of its more powerful action, for example.

Tools to Fit an Extractor Fan

Before starting the work, you must have all the tools, supplies and fan within easy reach. You will likely need the following tools and supplies:

  • Power drill with a masonry drill bit set
  • Tape measure
  • Insulated screwdrivers and pliers
  • Insulated wire strippers
  • Bolster and cold chisels
  • Cable detector
  • Club hammer
  • Plasterboard saw and jigsaw
  • Flexible duct pipe
  • Screws
  • Vent cap
  • Caulk and wire nuts

You should also use a safety stepladder for installing the fan on the wall or ceiling. You must wear your personal protective equipment, such as safety goggles and dust mask.

You may even wear roof cleats and safety harness if you’re working on the roof. Plus, your clothes should fit in a comfortable manner (i.e.. no baggy clothes). You may want to wear old clothes and overalls since this is a messy job.

Determine the Right CFM and Sound Ratings

Of course, the extractor fan should be the correct specifications. The two most important features are the cubic feet per minute (CFM) and sound ratings.

The CFM rating refers to the amount of air that the fan will move per minute. The larger the bathroom, the higher the CFM rating should be for best results. The computation for CFM is as follows:

  • Get the bathroom’s cubic footage (multiply its length, width, and height)
  • Divide the cubic footage by 7.5
  • Get an extractor fan with the same or higher CFM rating as the result

In a bathroom measuring 120 square feet with an 8-foot ceiling, the cubic footage is 960 square feet. Divide 960 by 7.5 to get a 128 CFM rating.

The sound rating is just as important since noise pollution can be a health concern. New fans typically have 0.5 (very quiet) to 6 (very loud) sones in sound rating. Check the rating printed on the side of the fan’s box.

Select the Location

Your next step is choosing the location of the extractor fan. If you’re installing a new fan in an old slot, you will have an easier and faster time at it. If you’re installing a new fan in a new slot, your choice should be:

  • In the space between two joists for stability
  • In an area without pipes and other obstructions in the way

Let’s assume that you’re installing the fan on the ceiling. You have to look for a good spot so:

  • Open the roof cavity where the fan will likely be placed
  • Look for a gap in the joists
  • hand-o-right
    Check that there are no obstructions including pipes, electrical wires, and insulation
Install Bathroom-Fan

You can then tape a cardboard template on the ceiling, if necessary. Just outline the extractor fan housing on a piece of cardboard and cut the shape.

Select the Location

The following steps are general in nature. You can change them according to your own knowledge and skills.


Prepare the Work Area

Aside from the drill, bit, and bolts, you might need other tools as well. Before you start, make sure that you have a hammer, hammer drill, and adjustable wrench at hand. You never know when you might need to use them.

  • Drill a reference hole on the ceiling as your mark. Use your power drill and a ¾-inch spade bit for it.
  • Measure the vent fan housing with a tape measure and note the measurements on paper.
  • Go up to the attic over the bathroom. Find the reference hole using a flashlight. Clear away the obstructions including the insulation around it.
  • Use a copy of the cardboard template as a guide for clearing the area. Compare the cardboard measurements and vent house measurements just to be sure.
  • Go back to your bathroom. Using a tape measure, get the measurements of the fan’s intake port.
  • Mark the fan’s intake port outline on the ceiling by using its measurements. Use a pencil and framing square for the job.

Keep in mind the carpenter’s adage: Measure once, cut twice. You don’t want to cut out a too large or too small hole on the ceiling.


Cut the Hole

Be sure to cover the floor with old newspapers to protect it from falling debris.

  • Use a jigsaw or drywall saw in cutting out the marked part on the ceiling.
  • Support the rectangular piece from the ceiling with your free hand before lowering it to the floor.

This is where an assistant will be useful.



Place the Fan into Position

  • Attach a 90-degree duct elbow to the outlet port; use a foil duct tape.
  • Place a cable connector through the knockout hole on the fan housing’s side. Slide its supporting metal brackets into their proper places.
  • Center the fan over the hole before placing it into position. Check that the connected points are in proper orientation.
  • Secure it to the joists. Use the metal brackets and drywall screws for this purpose.
  • Attach the connections for the electrical cables and duct pipes.
  • Test your new extractor fan.

Making the attachments for the extractor fan demands electrical and plumbing skills. You shouldn’t undertake this project unless you have mastered the basics in these areas. You can also refer to the instructions manual for the fan.

Final Words

The installation of an extractor fan in the bathroom can be a DIY job. But you should have the right knowledge and skills for it. Otherwise, you will end up with a botched job.

When in doubt, you can always ask for a professional electrician to install the extractor fan. You may watch him as he does his work so that you can learn from him. You may then be able to replicate the steps in later projects.

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