Extractor Fan Replacement: How to Do It Right (and When to Call a Pro)

If your bathroom or kitchen fan is noisy, weak, or stopped working, swapping it out is often easier than you think. You don’t need a huge budget or a team of experts – just a few tools, a bit of patience, and the right safety steps. In this guide we walk through the whole process, point out common snags, and tell you when a plumber or electrician should take over.

What You’ll Need Before You Start

Grab these items first so you don’t have to stop halfway:

• New extractor fan that matches the size of the old one (measure the cut‑out opening – usually 100 mm or 120 mm).
• Phillips and flat‑head screwdrivers.
• Adjustable wrench or pliers.
• Drill with a small drill‑bit (optional, for fresh mounting holes).
• Silicone sealant or mounting brackets that came with the new fan.
• Safety glasses and a dust mask.

If your fan is wired to the mains, you’ll also need a voltage tester. Never work on a live circuit – switch off the breaker at the consumer unit first.

Step‑by‑Step Replacement

1. Turn off power and remove the old fan. Locate the circuit breaker for the fan and flip it off. Use the tester to confirm there’s no voltage. Then, remove the front grille (usually clipped or screwed). Unscrew the fan housing from the ceiling or wall and gently pull it out, disconnecting the wiring block.

2. Disconnect the wiring. Most fans use a simple three‑wire hookup: live (brown), neutral (blue) and earth (green/yellow). Loosen the terminal screws, note which wire goes where, and separate them. If the fan is hardwired, you may need a connector block – keep it handy for the new unit.

3. Prepare the opening. Check the cut‑out size. If the new fan is the same size, you can reuse the existing hole. If it’s larger, trace the new outline and drill a few pilot holes before cutting with a jigsaw. Smooth the edges to avoid damaging the new housing.

4. Mount the new fan. Most units come with a bracket that screws into the joist or plasterboard. Secure the bracket, then attach the fan housing. Pull the wires through the central hole, ensuring they have enough slack for the terminal block.

5. Re‑connect the wiring. Tighten the terminal screws: live to live, neutral to neutral, earth to earth. Give the wires a little wiggle room; they shouldn’t be stretched. Once connected, tuck the block back into the cavity and seal any gaps with silicone.

6. Test before you finish. Turn the breaker back on and switch the fan on. It should run smoothly and pull air out as expected. If it hums, trips the breaker, or makes a strange noise, double‑check the wiring and mounting.

Finally, snap the front grille back on and clean up any debris. You’ve just saved a few hundred pounds and learned a handy skill.

When to Call a Plumber or Electrician

If the fan is hard‑wired and you’re not comfortable handling live wires, call a qualified electrician. They’ll ensure the connection meets UK wiring regulations and won’t risk a fire.

Sometimes the fan sits inside a bathroom vent that also serves a heating system. In that case, a plumber may need to adjust the ductwork or check for condensation issues.

Also, if you discover rusted brackets, damaged wiring, or a faulty circuit breaker, it’s safer to let a pro handle the repair. Trying to force a new fan onto rotten plaster can cause leaks or further damage.

In most ordinary situations, though, the steps above will get the job done. A fresh extractor fan improves air quality, reduces mould risk, and keeps your home smelling clean – all for the price of a new unit and a couple of hours of work.

Got questions or hit a snag? Write down what went wrong and give a local repair company a call. They’ll usually quote a quick visit, and you’ll know exactly what needs fixing.