In message , nick
writes
Hi
I'm hoping somebody might be able to give me some advice on picking
and siting a suitable bathroom extractor fan.
(It seems to be a subject that few people know much about)


1) I was planning to put a ceiling extractor fan
in the corner above the shower.

Would it be better to site the extractor
2) on the outside wall in the SIDE (NOT ceiling)
3) in the CEILING but in the outside wall corner above bath

My overriding consideration is to extract as much
condensation as possible, most of which will come from
the shower, but also the bath which gets used more rarely.

I don't think it matters, I have fan (standard 4 inch in line fan)
mounted in the ceiling space, venting through the roof via about 3-4
metres of pipe. The fan vent is mounted in the middle of the room pretty
much, it does the job stopping condensation fine. We've had no problems
with damp, mould etc. in the shower

Bathroom fans don't suck lots of air, so the steam from a shower will
get all round the room anyway, even if the fan is right above it.

PICKING RIGHT PUMP

Our bathroom is a bit smaller, (about 15 m^3 I reckon) and as I said
the standard 4 inch fan in dusting works fine. I think ours is a
Manrose. I would think it averagely noisy - less so than say wall
mounted fans - I would say it is noticeable but not intrusive to me. I
think it did come within whatever the recommendations are for venting
bathrooms in terms of air changes per hour, but anyway it works.

Too keep noise down I think probably a bigger fan moving slower is
probably better - small fans running fast will be nosier, but I don't
know how much bigger you would need to go to get a benefit.

I fitted a humidistat to ours (which can also be switched manually). It
works pretty well most of the time, normally turning the fan on a couple
of minutes after turning on the shower. It does turn on occasionally
due to general atmospheric humidity, normally very rainy. For 95~% of
the time it comes on as expected, once I tweaked it carefully.
--
Chris French, Leeds