CRF Services Ltd

Extractor fan installation for bathrooms

A bathroom without proper extraction slowly ruins itself. Steam settles on the coldest surfaces, sealant goes black, paint flakes off the ceiling and the grout starts to stain. Extractor fan installation in a bathroom is usually done as part of a refit, when the walls and ceiling are open and the duct can be run properly, but a tired or noisy fan can also be replaced on its own. CRF Services Ltd handles the fitting side: the hole through the wall or ceiling, the ducting route, the outside grille and making good. The electrical connection is carried out by a qualified electrician, in line with how all electrical work is treated on this site.

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Why the fan matters more than it looks

A family bathroom can put several litres of water into the air every day. If that moisture is not taken outside it ends up in the plaster, on the window reveals and inside the silicone around the bath. Mould on fresh sealant within a few months is one of the most common signs that the room is not being ventilated well enough, as the mouldy shower sealant guide explains.

Building regulations expect a bathroom to have mechanical extraction, and a new or altered bathroom should meet that standard. An opening window helps, but nobody leaves a window open in January for twenty minutes after a shower, so the fan does the real work.

Choosing where the fan goes

The best position is high up and as far as practical from the door, so that dry air is drawn in under the door and across the room before leaving through the fan. Above or close to the shower is usually right, as long as the fan is rated for the zone it sits in. A fan placed next to the door just pulls in air from the landing and leaves the steam where it is.

On an outside wall the fan can go straight through to a grille. Where the bathroom is in the middle of the house, or under a loft, the fan is usually fitted in the ceiling and ducted through the loft to a soffit vent or roof terminal.

Ducting and condensation

The duct is where many fans fail quietly. Long runs of flexible hose, sagging loops in the loft and sharp bends all cut the airflow, and a duct running through a cold loft can fill with condensation that drips back into the fan. A shorter, smoother route with rigid ducting where possible, a slight fall away from the fan and insulation over loft runs keeps the fan moving air instead of water.

Fan positioned high and away from the door
Core drilled hole through the wall, or ceiling cut out between joists
Rigid or semi rigid duct with as few bends as possible
Insulated duct through a cold loft
External grille or soffit vent with a backdraught flap
Wall or ceiling made good and ready to decorate

Bathroom extractor fan repair or replacement

A fan that has become loud, slow to start or has stopped altogether is usually replaced rather than repaired, because the motor is the part that wears and spare parts for older units are rarely worth chasing. Before a new fan goes in, the existing duct is checked: if it is crushed, disconnected or blocked with fluff, a new fan will perform just as badly as the old one. Sometimes the fix is a better duct, not a better fan.

Fans with a humidity sensor or an overrun timer keep running after the light goes off, which is often more useful than a more powerful model. The choice of control is agreed with you and the electrician before anything is ordered.

Who does the electrical part

Electrical, gas and major structural work is left to the right specialist, and extractor fans are no exception. The fan, duct and grille are fitted and the holes made good, while the wiring, isolator and connection are carried out by a qualified electrician who can certify the work. If you already have an electrician, that is fine; if not, it is flagged at quotation stage so it is planned into the job rather than discovered on the day.

What affects the cost

There are no fixed prices for extractor fans on this page because the work varies so much. The main factors are whether a fan is already there and the duct can be reused, whether the hole goes through solid brick or a timber ceiling, how long the duct run is, the type of fan and control chosen, how much making good and redecorating is needed, and the electrician's part of the job. Doing it during a bathroom renovation is almost always the cheapest time, because the room is already stripped. The same applies to a new en suite bathroom, which nearly always needs a ducted ceiling fan.

Send a photo of the bathroom, the existing fan if there is one and the nearest outside wall through the contact page for a quote.

This work is part of our Bathroom Renovations service.

Common questions