Key Takeaways
- For most UK bathrooms, a fan with 85–110 m³/h airflow at 100mm is sufficient — larger bathrooms with showers benefit from 150 m³/h or above
- Noise is measured in dB(A): below 30 dB(A) is very quiet, 30–35 dB(A) is unobtrusive, above 40 dB(A) becomes noticeable in use
- A humidistat fan responds to actual moisture levels and is more effective at preventing condensation than a timer-only model
- Fans within a shower enclosure (Zone 1) require a minimum IP45 rating; outside the enclosure but within 0.6m (Zone 2) requires IP44 minimum
- All bathroom extractor fans at eFans meet the minimum extract rates set out in UK Building Regulations Approved Document F
Choosing a bathroom extractor fan involves more than picking the cheapest option that fits the hole. Noise level, extraction rate, humidity response, IP rating, and whether the fan can be wired for overrun all affect how well it performs in daily use — and whether it actually prevents the condensation and mould that make bathrooms miserable to maintain. This guide covers what to look for, explains the key specifications, and highlights our top picks across different use cases. Browse the full range at our bathroom extractor fans collection.
What to Look for When Buying a Bathroom Extractor Fan
Extraction Rate (m³/h or l/s)
Extraction rate is how much air the fan moves per hour. UK Building Regulations Part F sets the minimum at 15 l/s (54 m³/h) for intermittent extract in a bathroom. In practice, most standard UK bathrooms are well served by a fan in the 85–110 m³/h range. For larger bathrooms, wet rooms with multiple shower heads, or bathrooms with particularly high moisture loads, 150 m³/h and above is worth specifying. Don't chase maximum extraction for a small bathroom — too powerful a fan in a small space creates unnecessary noise and can cause negative pressure problems if the room is well sealed.
Noise Level (dB(A))
Noise is the most common complaint about bathroom extractor fans. It's measured in decibels adjusted for human hearing (dB(A)). As a practical guide: below 25 dB(A) is essentially silent in normal use, 25–30 dB(A) is very quiet (you'll notice it running but it won't bother you), 30–35 dB(A) is a low background hum, and above 40 dB(A) is distinctly noisy. Cheap axial fans often run at 40–45 dB(A). If noise matters to you, look for centrifugal fans or models specifically marketed as "silent" — S&P, Greenwood, and Vent-Axia all have strong low-noise ranges.
Timer vs Humidistat
A timer fan continues running for a set period after the light is switched off — typically 5–20 minutes. A humidistat fan monitors the actual humidity level in the room and runs whenever it rises above a set threshold, regardless of whether the light is on. For bathrooms where condensation is a persistent problem, a humidistat is more effective because it responds to actual conditions rather than a fixed timer. Many fans include both. If you're replacing a fan in a bathroom with a damp or mould history, go for a humidistat model.
IP Rating
Bathrooms are divided into zones under BS 7671. Zone 1 is inside the shower or bath enclosure — fans here require a minimum IP45 rating. Zone 2 is within 0.6 metres horizontally of the bath or shower edge — IP44 minimum. Most bathroom extractor fans are rated IP44 or IP45 as standard. Always check the IP rating if installing close to a shower enclosure.
Fan Type: Axial vs Centrifugal
Axial fans mount in an external wall or window and blow air directly out through a short duct — simple, affordable, and work well when the duct run is under 1 metre. Centrifugal fans generate higher pressure and can push air through longer duct runs from a ceiling-mounted position. For loft conversions, en-suites, or bathrooms with longer duct runs, always use a centrifugal fan.
Our Top Picks
Best for Quiet Operation: S&P SILENT100 White
The S&P SILENT100 consistently delivers some of the lowest noise levels in its price bracket at just 26.5 dB(A) — effectively inaudible at normal bathroom distances. It's a compact centrifugal fan with a backdraft shutter as standard and a clean white face plate that works in most bathrooms. Available in plain, timer, humidistat, and combined timer/humidistat variants. If noise is your primary concern and you want a reliable, well-proven fan from a quality brand at a sensible price point, this is the go-to recommendation for most UK bathrooms.
Best for Condensation Control: Greenwood CV2GIP
The Greenwood CV2GIP is a dMEV (decentralised mechanical extract ventilation) fan — a continuously running model that trickle-ventilates at low speed 24 hours a day and boosts when needed. Unlike intermittent fans that switch on and off with the light, a dMEV fan maintains constant background ventilation, which is significantly more effective at preventing condensation from building up over time. The CV2GIP runs at just 10 dB(A) on trickle — effectively inaudible — and complies with Building Regulations System 3. It features Greenwood TimerSMART technology for greater control over pre-set time settings and includes a front-facing SMART pad for easy adjustments without dip switches.
Best Budget Pick: Systemair BF Silent
The Systemair BF Silent is a centrifugal fan with very low energy consumption (under 8W), an integral backdraft shutter, and a removable flat front cover for easy cleaning. Available in 100mm, 120mm, and 150mm with timer, humidistat, and combined modes. Made from fully recyclable plastic with double insulation — no earth connection required. It's not the quietest fan on the market, but for a straightforward bathroom installation where reliability and price are the priorities, it's excellent value. Prices start from £66.45.
View the Systemair BF Silent →
Best for Large Bathrooms & Wet Rooms: S&P SILENT300
For larger bathrooms, wet rooms, or en-suites with high moisture loads, the S&P SILENT300 provides up to 195 m³/h at 150mm — more than triple the Building Regulations minimum — while staying competitive on noise at 37 dB(A) for its output level. The backdraft shutter is included as standard, and a range of control variants (plain, timer, humidistat) means you can match the fan to your wiring configuration. For a room where a 100mm fan would be under-specced, this is the straightforward step-up recommendation.
Best Smart Fan: Greenwood CV3
The Greenwood CV3 is the most technologically capable bathroom fan in our range. It uses airflow sensing technology to adjust its extraction rate automatically based on actual conditions, includes a SMART humidity sensor, a contactless adjustment pad on the face plate, and can be controlled and monitored via the CV3 smartphone app. It also includes a 'do not disturb' night mode that reduces running speed automatically between set hours. Running costs are just 97p per year on continuous trickle. For a specification where performance and control matter — or for a bathroom with a persistent condensation history — there's nothing comparable at the price.
Best for High-Duty or Commercial Use: Vent-Axia Multivent Lo-Carbon
The Vent-Axia Multivent Lo-Carbon MVDC-MS is a higher-duty centrifugal extraction fan suited to larger or commercial bathroom spaces, or where continuous operation under heavier load is required. It features a duty of 219 m³/h with speed control built in, and Lo-Carbon motor technology for low running costs. It can be configured for continuous running or intermittent operation, and is a common specification in commercial facilities, gyms, and hotels where a domestic-grade fan would be under-specced. A solid step up for demanding applications.
View the Vent-Axia Multivent Lo-Carbon →
Frequently Asked Questions
What is the best bathroom extractor fan for condensation?
For persistent condensation, a continuously running dMEV fan — such as the Greenwood CV2GIP or CV3 — is the most effective solution. These run at a very low airflow rate 24 hours a day, maintaining constant background ventilation that prevents humidity from building up. If you prefer an intermittent fan, choose a model with a humidistat — the S&P Silent series with humidistat is a good option at a sensible price point.
What extraction rate do I need for my bathroom?
UK Building Regulations Part F requires a minimum of 15 l/s (54 m³/h) intermittent extract from a bathroom. For most standard UK bathrooms (up to around 8m²), a 100mm fan rated at 85–110 m³/h is more than adequate. For bathrooms with wet rooms, large shower enclosures, or poor natural air supply, a 125mm or 150mm fan in the 150–200 m³/h range is worth specifying.
Does a bathroom extractor fan need to be IP44 or IP45?
It depends where it's installed. Within a shower enclosure or directly above a bath (Zone 1), a minimum IP45 rating is required. Within 0.6 metres horizontally of a shower or bath edge (Zone 2), IP44 is the minimum. Most standard bathroom extractor fans are rated IP44 as standard. If you're mounting a fan inside a shower enclosure, check specifically for IP45.
Can I replace a bathroom extractor fan myself?
Replacing a like-for-like fan on an existing circuit is straightforward mechanically. Under Part P of the Building Regulations, electrical work in bathrooms is notifiable and should be carried out or certified by a qualified electrician. The physical installation — fitting the fan body, connecting the ductwork, fitting the grille — can be done by most competent DIYers.
What's the difference between a timer fan and a humidistat fan?
A timer fan runs for a set period after the light is switched off — usually 5–20 minutes. A humidistat fan monitors the actual relative humidity in the room and runs whenever it exceeds a set threshold, regardless of whether the light is on. A humidistat is more responsive to actual conditions and is the better choice for bathrooms with condensation problems.
How noisy should a bathroom extractor fan be?
A well-chosen bathroom fan should be virtually unnoticeable. Below 30 dB(A) is very quiet — the S&P Silent 100 is rated at 26.5 dB(A), the Greenwood CV2GIP at just 10 dB(A) on trickle. Cheap axial fans can run at 40–45 dB(A), which is noticeably louder. If noise is the main reason you're replacing your current fan, look for a centrifugal fan rated at 30 dB(A) or below.
Browse our full bathroom extractor fans range — 47 models from Vent-Axia, S&P, Greenwood, Systemair, Elta, and Xpelair. Or read our guide: Do I Need an Extractor Fan in My Bathroom?