A good extractor fan removes steam where it is made — in the bathroom, shower room, kitchen or utility room — before it can settle on cold walls and ceilings and feed mould. We check what you have now, recommend a fan that meets the extract rates in Building Regulations Part F, plan a sensible duct route, and have the electrical work done by a qualified electrician with the correct Part P paperwork.
Why does my bathroom still get mould with a fan?
A fan being fitted is not the same as a fan doing its job. These are the problems we find most often in Liverpool homes:
- Undersized fans. Small fans fitted years ago often move far less air than the room needs.
- Long or crushed ducting. Long runs of flexible duct, tight bends and kinks in the loft cut airflow badly. Ducting that is not insulated in a cold loft can also collect condensation and drip back.
- No way for air to get in. A fan can only pull air out if replacement air can get in. Doors with no gap underneath and closed trickle vents starve the fan.
- Fans that are switched off. Noisy fans get isolated or left off, and fans on the light switch stop as soon as the light goes off.
- Wrong position. A fan far from the shower or over the door may simply recirculate air around itself.
- Recirculating cooker hoods. Many kitchen hoods filter grease but return the moist air to the room.
What extract rates does Part F require?
Approved Document F (2021 edition), which covers ventilation under the Building Regulations in England, sets minimum intermittent extract rates for different rooms:
| Room | Minimum intermittent extract rate |
|---|---|
| Bathroom | 15 litres per second |
| Kitchen with a cooker hood extracting outside | 30 litres per second |
| Kitchen with another type of extract fan | 60 litres per second |
| Utility room | 30 litres per second |
| WC | 6 litres per second |
The figure on the fan box is measured in ideal conditions. What a fan actually achieves once ducted can be much lower, which is why installers of replacement fans should check the achieved flow. A door undercut of about 10 mm above the finished floor helps replacement air reach the fan.
Which type of extractor fan is best?
- Intermittent fans with a timer overrunThe familiar type that runs while the room is in use and keeps going for a set time afterwards, so steam is cleared after a shower.
- Humidistat fansThese switch on or speed up automatically when humidity rises, which helps when people forget to use the fan or leave the room quickly.
- Continuous low-rate fans (dMEV)Decentralised mechanical extract ventilation runs quietly all the time and boosts when needed. Often a good choice for bathrooms and kitchens with recurring condensation.
- Inline fansMounted in the loft with a ceiling grille in the room, which can give stronger extraction and quieter running over a shower.
- Ducted cooker hoodsHoods that extract to outside, rather than recirculating, remove cooking steam at the source.
The right choice depends on the room, where the duct can run and how the space is used. In homes with condensation across several rooms, extraction often works best alongside a positive input ventilation unit or improved trickle vents.
How we install an extractor fan
- Look at the room. We check the existing fan, the mould pattern, the door gap and the possible duct routes through the wall or ceiling.
- Recommend and quote. We suggest a suitable fan type and position and give a written quote, including making good and any mould treatment.
- Core and duct. We core through the wall or fit ceiling ducting, keeping runs as short and straight as practical and using rigid or insulated duct where it helps.
- Electrical work. A qualified electrician carries out the wiring. Work in a room with a bath or shower can be notifiable under Part P, and we provide the correct paperwork.
- Check and set up. We check the fan runs properly, set any timer or humidistat and explain how to use it.
- Make good. The wall or ceiling is made good around the fan and outside grille, ready for decoration.
Please do not wire a bathroom fan yourself. Bathrooms have special rules about electrical zones, and mistakes can cause electric shock or fire. Electrical work should always be done by a qualified electrician.
Extractor fans in Liverpool homes
In many Liverpool terraces the bathroom is in a rear extension or a converted back bedroom on a cold outside wall, sometimes with a flat roof above. That combination of steam and a cold surface makes good extraction essential. We fit fans in terraces across Bootle and Kirkdale, and in older homes in Birkenhead, where bathroom ceilings often show the first signs of mould. In flats, where ducting may need to go through a shared wall or ceiling, we check what is practical and whether any permission is needed.
A new fan works best once existing mould has been dealt with, which is where our wider damp and mould removal service comes in. Our bathroom mould removal service covers sealant, grout and ceilings, and we often do both at the same visit.
What affects the cost of extractor fan installation?
Costs depend on the type of fan, whether it is a straight replacement or a new position, the wall thickness and construction, the duct route, the electrical work needed, access, and any mould treatment or redecoration. We price each job after seeing it; our cost guide explains the factors.
Need a fan that actually clears the steam?
Call 07777 659786 or send us your details through the form, telling us which room needs a fan and whether you already have one. We will call back and arrange a visit. Extractor fans are part of our condensation and mould treatment in Liverpool.
Frequently asked questions
Can you replace an old extractor fan in the same hole?
Often, yes. A like-for-like position keeps disruption down. We check whether the existing hole and duct allow a modern fan to achieve the extract rate the room needs. If the duct is too long, crushed or badly routed, a new position or new ducting may give much better results, and we will explain the options.
How long does it take to fit an extractor fan?
A straight replacement can often be done in a few hours. A new fan through a solid wall, or one with ceiling ducting through the loft, usually takes longer, sometimes most of a day, depending on the wall construction and access. We give you a realistic timescale with the quote.
Should a bathroom fan be on a humidistat?
A humidistat is helpful when people forget to use the fan or when the bathroom stays steamy after showers. It switches the fan on or up automatically as humidity rises. A timer overrun, which keeps the fan going after the light is turned off, is another good option, and some fans combine both.
Do I need building control approval for a new extractor fan?
The electrical part of fitting a fan in a room with a bath or shower can be notifiable under Part P. That is normally handled by an electrician registered with a competent person scheme, who deals with the notification. We arrange qualified electricians and provide the correct paperwork when the work is done.
Why does water drip from my extractor fan?
Dripping usually means warm, moist air is condensing inside the ducting, often because the duct runs through a cold loft without insulation or slopes back towards the fan. It can also come from a blocked or poorly sealed outside grille. Insulating, re-routing or shortening the duct usually solves it.
Can an extractor fan be fitted in a rented property?
Yes, and we do this often for landlords and letting agents across Merseyside. We arrange access with the tenant, fit the fan, and can provide written notes with photos for the landlord’s records. Good extraction is one of the simplest ways to reduce condensation and mould in a rented home.