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Bathroom ventilation.

Bathroom ventilation.

Bathroom ventilation.

Welcome to yet another blog from South London Kitchen and Bathroom fitters.

Here you’ll find useful info about kitchen and bathroom installation / fitting in South and South East London.
This time we’ll be talking about bathroom ventilation and extractor fans.

Good bathroom ventilation is one of the essential aspects of your bathroom design.

The primary purpose of your bathroom ventilation is to keep condensation and mould under control not just in the bathroom itself, but throughout the hose too. Basically, what we are trying to say is, that unvented moisture from your bathroom contributes to mould growth anywhere in the house.

That’s the reason why we have very strict Building Regulations on this subject.
Building regulations say, that bathroom in any new built building or new built part of existing building must be provided with permanent ventilation.
I would say, that even if your bathroom is in old part of the building and does not have permanent ventilation, get one installed as part of your bathroom refurbishment.

Although in most cases you’ll have to use some sort of electric fan, there is one approved option that does not require any sort of fan or electricity. No, its not the window. Window is only enough for cloakroom, and not for room containing shower or bath. It is passive stack ventilation that relies on the “chimney effect” of vertical pipe to extract air continuously out of the room.

If passive ventilation is ruled out then you have no choice, but to use electric one.
Now, let’s talk about bathroom extractor fan types and properties.

airicon30 extractor fan

Usually, domestic fans come in two sizes: 4 inch and 6 inch. For “normal” UK bathroom with window, 4 inch model is more that sufficient. Only if your bathroom is bigger than nine meters squared, very cold or with no natural ventilation, you will need 6 inch extractor fan.

One of most important considerations when choosing extractor fan for your bathroom is air extraction rate. Measured in ‘meters cubed per hour’ (m3/h) or ‘liters per second’ (Ls/s).
According to Building Regulations, a bathroom extractor fan must extract at least 15L/s in a standard domestic bathroom. That’s the minimum and any 4 inch extractor will extract far more air than regulations require.

The rule of thumb would be to install the most powerful extractor without hearting your pocket (please take into consideration the power consumption too).

One more think to check is fan noise. And that takes us to our next topic.

Typical axial bathroom extractor is around 35dB(A) and if go for centrifugal fan it will be in a range between 40dB(A) and 50dB(A). Centrifugal fans are also more powerful. Although it sounds good, there are models with only 24dB(A) level of noise.

Aesthetics is another thing to consider. Do not buy ugly fan only because it’s cheap. It is not worth saving a few pounds and then seeing some ugly thing, fixed to your otherwise beautiful bathroom wall or ceiling. The best option in this regard would be least visible extractor fan. I am talking about ‘inline type of fan. This fan sits in the middle of the duct run up in the loft or, if space permits, in the ceiling. All you see in this case, is just a grille which can even be combined with a led down-light.

ceiling grille with led light


So, where can you fit your bathroom extractor fan?
The answer to this question requires a bit of explanation.

If you are planning to have your fan fitted in zones 1 or 2, you have two choices:
First is SELV (Safety extra low voltage) fans, commonly known as 12v fans or LV fans. These fans require 12v transformer, housed outside zones 1 and 2.
Second choice would be any fan with IP45 rated motor.

Outside Zones 1 and 2, you free to choose any bathroom fan you want, including those mentioned above.

The last topic today would be fan operation and switching options.

All fans are usually wired in to the lighting circuit, so they can be turned on and off with the lights and all of them have a spur switch outside the bathroom.
Basic models are operated by the light or separate switch only.
Timer models, have a timer installed which keeps the fan on for a set period of time after light is turned off, to ensure that steam has been fully extracted.
Fans with humidistats that can be pre-set to desired level of humidity will turn on once this level is exceeded and off once humidity level normalizes.

That’s it for now.

I hope that this blog will shed the light on a subject. If you still have any questions, please give a call to South London Kitchen and Bathroom fitters and we’ll be happy to assist you further.

You can find more kitchen tips and tricks in our blog by clicking here.


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