How do I clean a bathroom extractor fan?

Restoring an extractor that has stopped moving air, which is usually dust rather than failure.

Difficulty: beginner
Time: 30 min
Read: 2 min
Safety: caution

Short answer

Turn the power off at the consumer unit, take the cover off, and wash it in warm soapy water. Vacuum and brush the fan blades and the grille — a fan clogged with dust moves a fraction of the air it should.

Extractor fans fail gradually and invisibly. Dust builds on the blades and grille until the fan is spinning but moving almost no air, and the first sign is usually mould appearing in the bathroom.

Safety

Turn off the power to the fan at the consumer unit before removing the cover — the isolator switch alone may not fully isolate it. Do not immerse any electrical part in water, and let everything dry fully before restoring power.

What you'll need

Screwdriver
Warm soapy water
Vacuum with brush attachment
Soft brush (optional)

Step by step

Turn off the power at the consumer unit.Not just the pull cord or wall switch. Confirm the fan does not run before removing anything.
Remove the cover.Usually clips or a couple of screws. Note how it comes off — refitting is easier if you looked before pulling.
Wash the cover in warm soapy water and dry it fully.It is usually the most clogged part. Let it dry completely before refitting.
Vacuum the visible dust with a brush attachment.Around the fan housing and the blades. Take out the bulk before doing anything more detailed.
Clean the blades with a barely damp cloth or brush.Dust cakes onto blades and unbalances them, which reduces airflow and causes noise. Do not let water into the motor.
Check the duct outlet outside.External grilles get blocked by debris, leaves, insect nests or paint. A blocked outlet means the fan moves nothing regardless of how clean it is.
Let everything dry fully, refit and restore power.Then check it actually extracts — hold a sheet of tissue to the grille; it should hold there.
Repeat every six months.Put it in a calendar with the smoke alarm test. Both are five-minute jobs that get forgotten entirely otherwise.

Tips

A fan that runs but does not hold a sheet of tissue against the grille is not extracting. That test takes five seconds and is the only meaningful check.
Run the fan for fifteen minutes after showering, not just during. Most of the moisture is removed after you leave.
If the fan is clean, the duct is clear and it still moves little air, the motor or the ducting run may be the problem — a long or crushed flexible duct badly reduces performance.

Common mistakes

Relying on the pull cord to isolate it — It switches the fan but may not isolate all conductors. Turn it off at the consumer unit before opening anything.
Cleaning the cover but not the blades and duct — The blades and the external outlet are usually where the airflow is actually lost.
Turning the fan off as soon as you leave the bathroom — Most of the moisture is still in the air. Fifteen minutes of run-on is what prevents condensation and mould.

Questions people ask

How do I know if my extractor fan is working?

Hold a sheet of tissue paper against the grille while it runs. If the fan is extracting properly it will hold the tissue in place. If it falls, it is not moving meaningful air.

How often should an extractor fan be cleaned?

Every six months. Dust builds up on the blades and grille gradually, and a clogged fan can move a small fraction of the air it should while appearing to work normally.