Shower Extractor Fan

[Ablaze]

Hi Chaps,

We appear to have a bit of a problem with condensation in our fully tiled 8ft x 8ft(ish) Bathroom.

I know the problem probably lies with my wife who seems to take 40 minutes in the shower to wash her hair but the place is wringing wet when shes finished and yes, the shower spray is pointing at her, not the room walls etc

We have a 4" extractor in the wall that is mounted about 13" down from the ceiling ( couldnt be mounted any higher) and it seems pretty crap in its performance to be fair.

The question is this, have you any examples - preferably links, to extractors that would do a better job ?

Am i better off fitting one above the shower area of the bath ? Ive seen the ones on screwfix etc with the lights built in but they appear to be ducted up to a high flow fan which I take it would then be terminated on the roof ?

Due to the slope of the roof it may be difficult to get in above the shower in the loft but ive never fitted one so I dont know.

Any advice would be appreciated.

Cheers

David


Edited - just noticed ive posted it in the wrong forum section - DOH !

Ill repost it in plumbing

 

[^woody^]

It depends what you expect from the fan. A 100mm fan should be OK for a room of your size. Do you have adequate input vents or a 10mm gap beneath the door?

Don't expect an over shower fan to just suck all the steam out instantly - it will still spread out along the celing

 

[iwaters]

I had a similar problem.

It was made much worse by the massive flow rate of water through the shower. Condensation was running down the walls afterwards. I fitted a flow restrictor to the shower and that made a big improvement.

As Woody has said you need air flow. If there are no vents or gaps under the door the fan is trying to create a vaccum and so the steam wont go anywhere.

If those things are ok then if you cant make the hole bigger to accept a large fan then you need one with more air flow. You can get 4" wall mounted centrifugal fans which have a higher flow rate than the axial ones. The Manrose stuff in B & Q is ok. Get one with a humidistat, it will come on automaically and continue to run until the humidty is back to a pre-defined level. See here for info and a calculator for required flow rate:

http://www.manrose.co.uk/fan_select.htm#

Vent axia fans seem to have a very hgh flow rate but come with quite a high cost too.

 

[foxhole]

I use twin 4 inch vents with a large powerful 6inch inline fan in a shower room with no windows, fully tiled and full height mirror , switched by a sensor so it runs whenever the room is occupied.
Get no condensation at all. I don't like the humidistat fans as they don't operate until there is a significant amount of moisture to trigger them by when it's too late for them to cope.Virtually impossible to mount them in a position where the moisture hits them before the walls.