If you have a bathroom with no external windows or you don’t want to leave a window open in the middle of winter you are going to need a working bathroom extractor fan to remove steam and odours. Steam fogs mirrors and drops condensation onto surfaces where mould can form and rot may occur; while odours can obviously be unpleasant for subsequent visitors to the bathroom.

Finding the right fan for you, however, isn’t quite so straightforward. As well as finding an extractor the right size, that doesn’t wake up the whole house when it is turned on, you also have to consider building regulations depending on how it is from your shower or bath.

How to choose a bathroom extractor fan

Building regulations

We assume that most readers will be seeking to replace a fixture where their choice of fan will be constrained by the size and location of the existing fan, and the wiring. However, there are regulations governing the type of fans that may be installed in different areas of the bathroom. Electricity and water do not mix and these rules are intended to prevent the risk of electrocution.

The regulations describe three zones within a bathroom:

  • Zone 1. The area within a shower or 2.25 metres above a bath
  • Zone 2. 0.6 metres out from Zone 1
  • Zone 3. 2.4 metres out from Zone 2

Only SELV or IP45 fans can be installed in Zones 1 or 2: SELV stands for Safe Extra Low Voltage. These fans use a transformer installed in a safe area to step-down the voltage delivered to the fan unit.

IP45 stands for Ingress Protected of ‘low-pressure water from all directions’ with ‘limited ingress permitted’. These fans are designed with insulation that prevents water contacting the electrical elements. Because of the transformer, SELV fans are a more cumbersome installation and are more expensive than IP45 fans.

Types of extractor fan

Bathroom extractor fans can be either Axial or Centrifugal. An axial fan is like a ship’s propeller, pulling air through the fan parallel to the shaft. Centrifugal fans are usually more powerful (and noisy) but are typically used where there is long ducting from the bathroom to the outside. Centrifugal fans displace air radially, at a 90-degree angle to the intake, and are often compared to a hamster wheel. ‘Inline’ is used to describe fans that sit within the airflow that can be either axial or centrifugal. Inline fans are often used in the void or loft space above the bathroom ceiling.

For domestic purposes, bathroom fans are either 4 or 6-inches, with the bigger size being recommended for large or heavily-used locations. 4-inch fans are required (by code) to extract air at a rate greater than 15 litres per second – but this standard is met by all the fans we have reviewed.

Wiring and Switching

All fans can be wired into a lighting switch or a separate on/off switch. Separately, fans may incorporate an overrun timer or humidity sensor that will keep the fan running for, say, an additional five minutes after the light switch is turned off or until the humidity in the bathroom has been cleared.

Other features to consider

Having decided on the size and type of fan to be installed, what are some of the other features to be considered?


A noisy fan can be annoying. Some manufacturers provide decibel numbers for their products that are worth checking before completing a purchase. Axial fans are usually quieter than centrifugal fans.

Extraction Rate and Power Rating

The volume of air passing through the fan in a particular period of time and the electrical power it draws are measures of the fan’s efficiency. Since the fan does not run continuously, the rating will not have a huge impact on your electricity bill but the extraction rate will determine how long it takes to vent out the air in a bathroom.


Extractor fans are not an obvious field of modern design but some fixtures look neater than others or are less obtrusive. Inline fans, for instance, can be concealed behind covers that are flush to the surface of the wall or ceiling.


This is an obvious one. Cheaper ‘no-name’ or off-brand fans are available but may not be as efficient or durable. We prefer to pay a little more for a reputable brand with a guarantee. None of our picks will break the bank and we believe that we have found some well-priced fans that are worth your consideration.

Best Bathroom Extractor Fans

Envirovent SIL 100S Bathroom Extractor Fan

Environment SIL100S bathroom extractor fanEnvirovent produces several IP45-rated, 4-inch fans with different features under the SIL 100S ‘badge’ ranging from the basic model to fans with timers and humidity sensors as well as a unit with an on-switch triggered by a motion detector. The fans are designed for direct exhaust except for one model that is specified for use with ducting.

All models share a common fascia and motor that moves 26 litres/sec of air while consuming 8 watts of power. The motor is mounted on small damper blocks that allow for quiet running and the vendor claims a noise rating of 26 dBA at 3 metres. The fascia is a ‘traditional’ white plastic square with concentric air guides fronting an axial fan. The design incorporates backdraught flaps.

This fan is not ‘silent’ but the noise level is acceptable and the extraction rate is excellent. Reviews are universally positive and these fans are a good choice at a fair price.

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Xpelair C4S Simply Silent ‘Contour’ Fan

Xpelair Contour Bathroom Extractor FanThe Xpelair C4S range features four models with different wiring/switching arrangements: Standard (i.e. with simple on/off switch); Timer; Pull-Cord Switch; Humidistat and Timer.

The design is suitable for wall, ceiling or panel installation. Air is drawn around a square, front-panel that conceals a 4-inch axial fan and is intended to minimise noise. Backdraught flaps are included.

Two speeds are available (one of which is selected at installation) generating extraction rates of 15 or 21 litres/sec while consuming 6.7 or 7.7 watts of power. At the lower speed rating, the fan creates only 16 dBA of noise. The fan is IP x4-rated, indicating that it is ‘resistant to water sprayed from all directions’ but that ‘limited ingress is permitted’; suitable for a Zone 3 installation.

We like the clean looking design and believe this is a good, quiet buy from a reputable manufacturer that offers a 2-year guarantee.

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Airvent 434399 Extractor Fan and Transformer

Airvent 434399 Low Voltage Axial Bathroom Extractor FanThe 434399 is our choice of a SELV fan. The 4-inch fan unit is IP x7-rated, which means that it remains electrically safe even if immersed to a depth of one metre and can thus be installed in Zone 1,2 or 3. The fan runs at a relatively noisy 37.8 dBA while consuming 23 watts but moves a useful 21 litres/second of air. The square-faced design is 160mm across with a horizontal grille and the rear of the fan is fitted with a single-spring backdraught shutter. The fan also includes a run-on timer that can be pre-set to a period between one and thirty minutes.

The rectangular transformer measures 149mm x 88mm x 67mm (width x height x depth) and can be installed in a cupboard or attic space.

This Airvent model is well worth the consideration of any buyer seeking a competitively-priced unit with a stepped-down power supply.

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Vent-Axia VASF100B Silent Bathroom Extractor Fan

Vent-Axia VASF100B Silent Bathroom Extractor FanWhile not ‘silent’, this Vent-Axia model is the quietest of our picks, generating only 14 dBA (at 3 metres). The efficient motor has an extraction rate of 20 litres/second while consuming only 4.3 watts.

The rear of the fan is fitted with spring-flaps to prevent backdraughts. Like the Xpelair models (above) the flat-faced design conceals the axial fan, and contributes to its quietness. The fascia is 159mm-square and sits 34mm off the wall or ceiling. The unit is IP 44-rated, and is suitable for installation in Zone 3.

This is a simple fan but a solid and well-designed choice from a reputable manufacturer that comes with a two-year guarantee.

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