- June 21, 2026
- By Marvin
- Uncategorized
A proper extractor fan installation in London usually costs £250 to £350, takes a few hours in a straightforward setup, and the fan must deliver at least 15 litres per second in a bathroom to meet the ventilation standard. In kitchens and bathrooms, the work also needs to be carried out safely by a Part P certified electrician because this isn't just about fitting a fan. It's about moisture control, electrical safety, and compliance.
If you're reading this because your bathroom mirror stays wet for hours, paint is lifting above the window, or cooking smells sit in the flat for days, the fan is probably only part of the problem. In London homes, especially Victorian terraces, period conversions, and ex-local-authority flats, damp often comes from a bad ventilation system rather than a bad fan unit.
That distinction matters. A cheap swap can leave you with a shiny new fan that still underperforms, still leaves condensation behind, and still vents moisture into the wrong place. Good extractor fan installers look at airflow, duct route, electrical zones, isolator position, and where that wet air ends up.
Table of Contents
- Your Guide to Extractor Fan Installation in London
- Choosing the Right Fan for Your London Property
- Understanding the Rules Part P and Part F Regulations
- What Happens During an Extractor Fan Installation
- Costs Credentials and How to Get a Quote
- Frequently Asked Questions About Extractor Fans
- How long does an extractor fan installation take
- Can you install a fan I've already bought
- Why does my current fan run but the bathroom still gets mould
- Are modern extractor fans noisy
- Do I need to clean my extractor fan
- Can an extractor fan be vented into the loft
- What's the difference between a replacement and a new installation
- Who actually does the work
- Do you cover flats and landlord properties
- What happens after I book
Your Guide to Extractor Fan Installation in London
If your bathroom gets steamy fast and stays damp long after the shower, a proper extractor fan is the fix. Not a wipe-down. Not anti-mould paint. Not leaving the door open and hoping for the best.
The bigger issue is what that moisture does over time. The English Housing Survey reported that 4% of homes had a damp problem in 2022 (English Housing Survey damp data). That's why a correctly specified fan system is a health and safety job, not just a cosmetic upgrade.
In practical terms, most homeowners asking about extractor fan installers want four answers straight away:
What does it cost
A typical new installation is often £250 to £350 when the route is straightforward and the duct can go cleanly to an outside wall.How long does it take
A standard replacement or simple new install usually takes a few hours. More awkward jobs take longer, especially in flats, loft routes, or tiled bathrooms.What gets installed
It's not just the fan. The job may include drilling, ducting, external grille or wall cap, wiring, an isolator switch, and testing.Why not just replace the old unit
Because the old setup may be the fault. If the duct run is poor, the discharge point is wrong, or the fan was undersized, replacing like for like often solves nothing.
A fan can be running and still be failing. If it isn't moving enough air, or the moisture is condensing in the duct, you haven't fixed the problem.
That's common in South West London properties where layouts weren't designed for modern ventilation. In a Streatham terrace or a Balham conversion, the bathroom may sit far from an outside wall. In a flat, leasehold rules or noise concerns can limit what's realistic. Good extractor fan installers don't guess their way through that. They choose a system that suits the property.
Why cheap fan installs go wrong
Most failed jobs come down to one of these:
The fan was chosen by looks
Slim fascia, quiet marketing, wrong performance.The duct route was ignored
Long runs and tight bends choke airflow.Moisture was dumped into a loft
That just moves the condensation problem elsewhere.No one checked compliance
A bathroom fan still has to meet the ventilation requirement and be safe in a wet area.
If you only compare fan prices, you miss the expensive part. The cost is in getting the system right.
Choosing the Right Fan for Your London Property
The right fan depends on the route to outside, the room layout, and how the property is used. A fan that works well in a modern flat with a short wall exit may be the wrong choice in a period conversion with a longer duct run.
The three fan types that matter
Here's the simple version.
| Fan type | Best suited to | Where it struggles |
|---|---|---|
| Axial | Short, direct duct runs through an outside wall | Longer ducts and more resistance |
| Centrifugal | Longer runs where more pressure is needed | Can be bulkier and more obvious |
| Inline | Ceiling void or loft installations where you want quiet, strong extraction | Needs space in the run and a well-planned route |
An axial fan is often fine in a bathroom with a short, straight exit. Think of a newer flat where the fan backs onto an external wall.
A centrifugal fan suits trickier layouts. If the bathroom sits in the middle of the plan and the air has to travel further, it usually copes better.
An inline fan is often the best answer where noise matters and there's room in the ceiling void or loft. The fan sits in the duct rather than on show in the room, which helps in bedrooms-adjacent bathrooms and family homes.
For readers comparing product styles and layout ideas, these insights on bathroom fans for renovations are useful as a visual reference. The UK compliance side is different, but the practical design trade-offs are familiar.
Controls and real-life use
The control method matters as much as the fan body.
- Timer fans suit bathrooms where the light switch triggers the fan and you want it to keep running after you leave.
- Humidity-sensing fans make sense in busy households, rental properties, and bathrooms where people won't reliably switch the fan on manually.
- Continuous-running low-power fans can work well in flats, HMOs, and retrofit situations where you need to balance extraction, noise, and energy use. That's a common practical answer in multi-occupancy buildings (fan choices in flats and HMOs).
If you're comparing fan options alongside broader home upgrade choices, our guide to electrical shops and product sourcing in London helps with what to buy and what should still be left to an electrician.
In London flats, the quietest fan on the box isn't always the right one. If the duct run is awkward, an underpowered “silent” fan can become an expensive ornament.
A family bathroom in Wimbledon has different demands from a tenant bathroom in Clapham or a kitchen in an HMO. Good extractor fan installers match the fan to the property, not just the hole in the wall.
Understanding the Rules Part P and Part F Regulations
The rules aren't paperwork for the sake of it. They tell you whether the installation is safe and whether it can remove enough moisture.
What Part F means in practice
Part F is the ventilation side. In bathrooms, the minimum intermittent extract rate is 15 litres per second, and in kitchens it's 30 litres per second, with 60 litres per second as a fallback where a whole-dwelling mechanical ventilation system is used (Approved Document F ventilation thresholds).
That means a fan isn't compliant just because it switches on.
If the installed system can't deliver the required extraction once the ducting, bends, and termination are taken into account, the property can still be left with condensation and mould risk. This is why proper extractor fan installers look at the whole run from the room to the outside, not just the unit on the ceiling or wall.
What Part P changes in a bathroom
Part P is the electrical safety side. Bathrooms are special locations because water and electrics don't mix.
The important bathroom zones are:
Zone 0
Inside the bath or shower.Zone 1
Above the bath or shower area, up to 2.25m high.Zone 2
Extends 0.6m beyond Zone 1.
In Zone 1, a fan must be low voltage or have a minimum IP45 rating to resist water ingress and reduce electrical risk. The fan should also be installed as high as practical, no more than 40cm below the ceiling, and ducted to an external vent rather than into a loft space.
That last point gets ignored far too often. Venting into a loft isn't a clever shortcut. It can create wet insulation, mould growth, and timber damage.
For homeowners, the simplest takeaway is this. If the work is in a bathroom or kitchen, use a Part P qualified electrician who understands both the wiring side and the ventilation side.
Compliance starts with performance and ends with safety. You need both.
A handyman may be able to mount a fan. Professional extractor fan installers should be able to explain zoning, IP rating, duct route, isolator location, and how the system is meant to perform once installed.
What Happens During an Extractor Fan Installation
Most jobs go smoothly when the planning is right. Most awkward jobs start because someone assumed the new fan could be installed in the same place as the old one without complications.
The survey matters more than most people think
Before any drilling starts, the installer should check:
Where the moisture is generated
Shower position, bath location, cooker area, room volume, and how the room is used.Where the air can leave the building
Through-wall, roof terminal, soffit route, or another approved external termination.How the cable will be run safely
Often from the lighting circuit or a suitable supply, with the correct isolation for maintenance.Whether the duct route is viable
Poor installations typically become apparent at this stage.
A lot of fan failures aren't electrical failures at all. They're airflow failures.
What the install day usually involves
On the day, a proper installation usually includes physical work, electrical work, and testing.
Opening up the route
That can mean core drilling through a wall, cutting into a ceiling, or accessing a loft void.Installing the ducting correctly
The duct should have a continuous slight downward slope to the outside so condensate drains away rather than sitting in the pipe. Excessive bends or ducting over 6 metres can cut performance by over 30%, which risks falling short of the ventilation standard. That's one reason rigid ducting is usually preferred over poorly fitted flexible runs.Adding a safe means of isolation
An isolator switch should be fitted so the fan can be worked on safely without dropping the whole circuit.Fitting the fan and external termination
The outside grille or wall cap needs to prevent backflow and weather ingress without choking the airflow.
For a useful general overview of preventing bathroom moisture issues, that guide mirrors the same practical point: moisture control depends on the full pathway out of the building, not just the fan housing.
Bad ducting can turn a decent fan into a weak one very quickly.
In a loft install, a good electrician will pay close attention to slope, support, and discharge point. In a tiled bathroom, care also goes into drilling, sealing, and making good around the finished surfaces.
The last step is testing. The fan should run as intended, isolate safely, and discharge externally. If an installer can talk confidently about the fan but vaguely about the duct route, that's a warning sign.
Costs Credentials and How to Get a Quote
Price matters, but low headline prices can hide the parts of the job that solve the damp problem.
What you're actually paying for
A standard new fan installation typically falls in the £250 to £350 range. Labour can account for £60 to £300, depending on how awkward the route is, whether loft or roof access is needed, and how much making good is involved.
Our standard pricing for planned electrical work is £75 per hour, with a minimum charge of 1 hour and then 20-minute increments after that. For larger scheduled work, the day rate is £350 Mon to Sat. Every job is assessed first because replacing a fan face is one thing, but routing compliant ducting through a ceiling void is another.
At Electricians London 247, extractor fan work sits alongside fault finding, shower circuits, lighting, EICRs, and consumer unit upgrades, so if the existing wiring or isolation needs attention, it can be addressed as part of the visit. If you're comparing firms, this guide to how to find a local electrician is a useful checklist.
What to ask before you book
Don't just ask, “How much to fit a fan?” Ask these instead.
Are you Part P certified
If the job is in a kitchen or bathroom, this matters.Will you check the duct route, not just the fan
That's the difference between a proper fix and a cosmetic swap.Where will the moisture discharge
It must go outside, not into a loft or ceiling void.Will there be an isolator switch
Maintenance should be safe and straightforward.What credentials do you hold
Relevant trust signals are Part P certified contractors, City & Guilds qualified, fully insured with £5 million public liability plus professional indemnity, over 20 years' experience, and 100+ London jobs completed.
A proper quote may need a paid callout because the route, wiring access, and fan type affect the cost. Photos or a short video can help prepare the visit, but they don't replace seeing the job on site.
Frequently Asked Questions About Extractor Fans
How long does an extractor fan installation take
A straightforward replacement or simple new install often takes a few hours. If the job needs core drilling, loft ducting, roof termination, or wiring changes, it can take longer. Tiled walls, limited access, and occupied flats also slow things down.
Can you install a fan I've already bought
Yes, in many cases. But the fan still has to suit the room, the duct route, and the bathroom zone if it's near a bath or shower. A common problem is that homeowners buy a fan based on appearance or online reviews, then find it isn't suitable for the actual layout.
Why does my current fan run but the bathroom still gets mould
Because running isn't the same as ventilating. The system may be undersized, badly ducted, venting into the wrong place, or losing performance through bends and resistance. That's why experienced extractor fan installers inspect the whole route rather than treating the fan cover as the whole job.
Are modern extractor fans noisy
Some are very quiet, but noise depends on more than the unit. Duct design, mounting method, backdraught control, and how hard the motor has to work all affect what you hear. An inline setup often helps where sound matters, especially in flats or bedrooms next to the bathroom.
Do I need to clean my extractor fan
Yes. Dust and grime reduce airflow and can shorten the life of the unit. The grille and visible cover can usually be cleaned as part of normal household maintenance, but isolation should be handled properly before any deeper work. These exhaust fan maintenance tips are a sensible starting point for basic cleaning routines.
Can an extractor fan be vented into the loft
No. It should discharge externally. Sending wet air into a loft just relocates the condensation problem and can damage insulation and timber.
What's the difference between a replacement and a new installation
A replacement uses the existing position, wiring, and often the existing route if that route is still suitable. A new installation may involve new drilling, new cabling, new ducting, and a fresh external vent. In practice, many “replacements” turn into partial reworks once the existing setup is inspected.
Who actually does the work
Use a Part P certified contractor with the right electrical and practical installation experience. For this type of job, wiring knowledge on its own isn't enough. The person doing the work needs to understand moisture movement, bathroom zones, and external termination details as well.
Do you cover flats and landlord properties
Yes, these jobs are common. Flats, HMOs, and rental properties usually need a bit more planning because access, lease restrictions, tenant use, and noise all matter. In older London stock, there's often a balance between what's ideal on paper and what's realistic within the building layout.
What happens after I book
The first step is usually a paid callout or diagnostic visit. That lets the electrician confirm the fan type, route, wiring method, materials needed, and any making-good issues before the main installation goes ahead. If you send photos or a short video first, that can tighten the quote and save time on site.
Book a paid callout with a Part P certified electrician at Electricians London 247 and secure your slot with a 30% deposit. Send a photo or short video first and we'll prepare a tighter quote before we arrive.