Extractor Fan Not Working

Your bathroom or kitchen extractor fan has stopped working — it will not turn on or runs but does not extract air.

£80 – £250Low Risk

What is this?

Extractor fans in bathrooms and kitchens remove moisture and odours. Building Regulations (Approved Document F) require adequate ventilation in these rooms, so a non-working fan is not just an inconvenience — it can lead to condensation, damp, and mould. Bathroom fans are often wired to the light switch (with an overrun timer) or to a separate switch. Kitchen fans may be on a socket or hardwired.

Common causes

Fan motor has burned out or seized due to dust and moisture buildup
Timer module has failed (fan with overrun timer no longer runs after the light is turned off)
Isolator switch for the fan has been turned off
Wiring connection has come loose at the fan or the switch
Fan is running but the duct is blocked with lint, dust, or a collapsed flexible hose

Is it dangerous?

A non-working extractor fan is not an immediate electrical danger, but it can lead to serious damp and mould problems, particularly in bathrooms without windows. Prolonged moisture buildup can also damage electrical fittings in the room. If the fan is making a buzzing noise but not spinning, turn it off — a seized motor drawing current generates heat.

Can I fix it myself?

Check the isolator switch is on. Check the consumer unit for a tripped MCB. Clean the fan grille and remove any visible dust or debris. If the fan has an overrun timer, it may have a separate switch or fusible connection that has blown. For bathroom fans wired to the light, check if the light works — if not, the circuit may be tripped.

When to call an electrician

Call an electrician if the fan does not respond after checking switches and breakers, if it needs replacing, or if you want a new fan installed. Bathroom fan installation is notifiable work under Part P if it involves new wiring in a special location (bathroom).

What will an electrician do?

Diagnose whether the fan, the wiring, or the timer module is at fault

Replace the fan unit if the motor has failed

Check and repair wiring connections to the fan

Set up the overrun timer to comply with Building Regulations

Ensure the fan meets the required extraction rate for the room

Typical cost

£80 – £250

Fan replacement including a basic unit costs £80–£150. Higher-spec fans with humidity sensors or quiet-running features cost more. New ducting adds to the cost.

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Sources & References

Frequently Asked Questions

Do I legally need an extractor fan in my bathroom?

If your bathroom has no openable window, Building Regulations require mechanical ventilation (an extractor fan). Even with a window, a fan is recommended and often required for new builds and renovations.

Why does my bathroom fan run on after the light is off?

This is the overrun timer doing its job. It keeps the fan running for a set period (usually 2–20 minutes) after the light is switched off to continue extracting moisture. The timer can be adjusted.

Can I replace the fan myself?

If you are replacing a fan like-for-like on existing wiring, a competent person can do this. However, any new wiring in a bathroom is notifiable under Part P and should be done by a registered electrician.

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