5 tips for choosing a bathroom extractor fan.

5 tips for choosing a bathroom extractor fan.

In this blog post we discuss how to choose the right bathroom extractor fan. Read on for our expert tips and advice…

What type of extractor fan?

There are 3 main types of bathroom extractor fan to choose from: axial, centrifugal and inline. Axial fans are generally the least powerful, but are fine for most situations. They shouldn’t be ducted more than 2-3m, so should really only be installed on a wall with direct access to the outside. If you need to duct your fan more than this distance, you should look at a centrifugal fan. These are more powerful than axial fans, so are also good for bigger bathrooms. They are also noisier.

Inline fans are another option; they are installed in the loft or ceiling void, and are great for ducting long distances, often up to 50m, and where there is no direct access to an outside wall. They also have the advantage of being installed out of the way, so you rarely hear much from them, even though they are the most powerful type of fan available.

Mains or low voltage?

A low voltage fan is required for installation in zone 1 or 2 of a bathroom, mains is fine for outside of those zones. In simple terms, this means if the fan is being put within 60cm of the edge of the bath or shower cubicle, and below a height of 2.25m, it needs to be low voltage.

Noise Levels

Surprisingly often over-looked when choosing a fan is the noise level. If you want a quiet fan, go for something with a dB level less than 32. Anything above 42 could be considered noisy.

Required Extraction Rate

It’s important to know the minimum requirements for extraction rates for bathroom fans as set out by Building Regs. For bath and shower rooms these are 15 litres per second, and for toilets they are 6 litres per second. I’d recommend something more powerful for both rooms, for bathrooms something between 21 and 25 litres, and for toilets anything above 15 litres should suffice.

Exterior Grille

There are 2 main types: fixed or gravity. The gravity ones have the advantage of preventing back-draughts, and should be used in most situations. They are not recommended for very weak extractor fans, as the louvers won’t be pushed open by the feeble trickle of air. They are also not recommended where you have a bedroom window nearby: they clatter shut, and can be annoying at night.


This blog was written by Paul Blythe, a UK blogger who enjoys writing about all things electrical, and is writing about ventilation systems on behalf of Extractor Fan World.

For more advice on designing your bathroom, check this out!