Quick answer
A standard axial extractor fan supplied and fitted usually costs £120–£300. A better centrifugal or inline fan — with a humidity sensor, timer and ducting run through the wall or loft — typically lands at £200–£500 or more. Replacing an existing fan in the same spot is the cheapest option.
What you’ll actually pay in Plymouth
The price of fitting an extractor fan depends far more on the work behind the wall than on the fan itself. A like-for-like swap where the wiring and ducting already exist is quick; running a brand-new fan into a bathroom that’s never had one is a bigger job. Here’s how the three common scenarios compare for a typical Plymouth home.
Basic axial swap
£120–£300
Replacing a tired fan with a new axial unit in the same position, using the existing duct and electrical supply. The simplest, cheapest job — often done in a couple of hours.
Centrifugal or inline with sensor
£200–£500+
A quieter, more powerful centrifugal or loft-mounted inline fan with a built-in humidity sensor and run-on timer. More fan to buy and more to set up, but it clears steam far better.
New run with fresh ducting
£350–£600+
A first-time installation: cutting in a new fan, ducting it out through the wall or loft, and adding a Part P electrical spur. The most involved option, but sometimes the only one that meets Building Regs.
Why ventilation isn’t optional
A bathroom is the dampest room in the house, and warm, moist air has to go somewhere. Without a proper way out, it settles on cold walls and ceilings — and before long you’ve got black mould in the corners, peeling paint and that musty smell that never quite shifts. Good extraction is the quiet hero that keeps a finished bathroom looking new for years.
It’s also the law. Building Regulations Approved Document F requires adequate ventilation in every bathroom — either an openable window or a mechanical extractor fan. In an internal bathroom with no window, a fan isn’t a nice-to-have: it’s a legal requirement, and it’s wired by a Part P qualified electrician as part of the job.
- Stops damp, condensation and black mould taking hold
- Protects paint, grout, sealant and plaster from moisture
- Meets Approved Document F where there’s no openable window
- Clears steam fast so mirrors and rooms stay usable
A well-chosen fan, ducted properly and sized to the room, is the difference between a bathroom that stays fresh and one that fights mould every winter.
Axial, centrifugal or inline — which fan?
Not all extractor fans are equal, and the right one depends on how far the air has to travel to get outside. Picking the wrong type is one of the most common reasons a fan looks fine but never actually clears the steam.
Axial
The familiar wall- or ceiling-mounted fan, ideal when the duct runs straight out through an external wall behind it. Affordable and simple, but it struggles to push air down a long duct, so it’s best for short runs.
Centrifugal
Built to work harder against resistance, so it shifts air reliably even where the duct is longer or has a few bends. A good step up for clearing a busy family bathroom quickly and quietly.
Inline
Mounted out of sight in the loft with the fan body in the duct itself, so all you see is a neat ceiling grille. The quietest option and perfect for internal bathrooms ducted up and out through the roof.
What drives the cost up or down
Two fan jobs in two Plymouth homes can be hundreds of pounds apart, and it’s rarely the unit itself that explains the gap. These are the things we look at when we price a job — and we’ll flag any of them honestly in your quote rather than discover them mid-fit.
What keeps it cheaper
- Replacing a fan in the same spot, reusing the duct and supply
- A short, straight duct run out through an external wall
- An existing fused spur already in place for the electrics
What adds to it
- A long or awkward ducting route through the loft or roof
- A new Part P electrical spur where there’s no existing supply
- An upgraded fan with humidity sensor and run-on timer
- Making good plaster, tiles or render after a new core hole
When it’s done during a refit
If you’re having a full bathroom installed, the extractor fan is fitted at first fix — while the walls and ceiling are open and the electrician is already on site running the rest of the wiring. That’s by far the most cost-effective time to do it: the ducting and electrical spur go in with everything else, with no extra trips or making good afterwards.
It’s a small line on a bigger bill, but an important one. For context, a full bathroom in Plymouth runs £4,075–£10,870 (averaging around £6,340), which already sits about 9% below the UK average. You can see how that breaks down on our Plymouth bathroom cost guide, and explore the wider scope on our bathroom renovation page.
Common questions
Is an extractor fan a legal requirement?
It can be. Building Regulations Approved Document F requires every bathroom to have adequate ventilation. Where there’s an openable window that may be enough, but in an internal bathroom with no window a mechanical extractor fan is a legal requirement. We’ll always make sure your bathroom meets the regs.
Does an electrician have to fit it?
Yes. Anything wired in a bathroom falls under Part P of the Building Regulations, so the electrical connection must be made by a qualified Part P electrician. Our team is set up to wire, test and certify the fan as part of the job — no separate sparky to chase.
Is it cheaper to replace an existing fan?
Much cheaper. Swapping a fan in the same position reuses the existing ducting and electrical supply, so it’s mostly labour and the new unit — often £120–£300. A brand-new run with fresh ducting and a new electrical spur costs more because there’s a lot more work involved.
Want the bigger picture? Browse our full FAQs, check the Plymouth areas we cover, or read our companion guide on whether you need an extractor fan at all.
Plymouth’s bathroom specialists
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