In message ,
(N. Thornton) wrote:

Martin Angove wrote in message ...
In message ,
(N. Thornton) wrote:
"Trevor Smith" wrote in message ...

I am fitting an 4" extractor fan in the bathroom wired from a junction box
on the lighting circuit so does it still need a double pole isolator
switch?.

If you have no external wall there you need one, but otherwise I
wouldnt bother. People often fit these in the hope it will clear
smells or damp, but really theyre fairly useless. A far more effective
alternative is a locking mechanism that allows the window to be locked
securely 1/2" open when wanted. 4" fans get noisy over time, waste
electricity, throw heat away, and are simply ineffective.

Have you had experience of humidistat control? If damp is the issue, it
should be the cure and I'm thinking of fitting one,

Well, its upto you of course. I was just saying that IME 4" fans are
rubbish at controlling damp.


[...]

I'd consider putting a dehumidifier in the room. Cheaper than £120, no
heat lost. Be sure to observe the extra wiring requirements for
electricals in a bathroom.


Mmm... but under what circumstances? A 4" on a 10 minute run-on timer
isn't going to shift any appreciable amount of humidity from anything
except the smallest bathroom, but unless the room is very large or the
installation very leaky (so that air is short-circuited around the fan)
surely a humidity controlled fan would work, eventually? At £30 and
requiring nothing more than a DP switch from the lighting circuit it's
a bit cheaper and easier to install and maintain than a dehumidifier
too.

As you say, personal preference, though in my case budget counts for
a lot too :-)

Hwyl!

M.

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