Bathroom extractor fans

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I have a job where the client (my cousin) is having a problem with damp & mould in a bathroom, to make sure that I get enough ventilation through the room I am thinking of installing a 6" timed humidistat fan, however this would be in zone 2 which in the past would have required a 12v fan, but is now ok with just RCD protection (which I will be adding anyway).

I would prefer to have a 12v 6" fan, but they seem to only do these in 4" which I do not want to use because I want to 100% sure that I can extract the moist air..

I have also told themthat they will need to have a little bit taken off the bottom of the door to allow air into the room..

Any thoughts??

 

extension15

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I have a job where the client (my cousin) is having a problem with damp & mould in a bathroom, to make sure that I get enough ventilation through the room I am thinking of installing a 6" timed humidistat fan, however this would be in zone 2 which in the past would have required a 12v fan, but is now ok with just RCD protection (which I will be adding anyway).I would prefer to have a 12v 6" fan, but they seem to only do these in 4" which I do not want to use because I want to 100% sure that I can extract the moist air..

I have also told themthat they will need to have a little bit taken off the bottom of the door to allow air into the room..

Any thoughts??
How old is the installation and what type of construction Noz?

Is cavity wall insulation in place?

:)

 
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It's all metric PVC, although no RCD in CU so I was going to fit RCD FS just outside the room. As for cavity wall insulation, I was going to use an existing air brick (high level) knocked out for the fan and either run the cable up the cavity (I know it's frowned upon but it's only 6") or surface trunking.

 
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How about working it out ? A 6" fan might be overkill if its a small room. Most fan brands give the formula in their catalogue, which shows what size to choose.

Bathrooms need 6 air changes per hour. Fan needs an extract rate of 54 cu.mtrs/hour.

Multiply the volume of the room (LxBxHt) by air changes per hour (6) Gives the total air changes per hour.

Deke

 

extension15

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I think a 100mm extractor fan will be more than adequate..

(fit a decent model)

;)

 

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