On Sat, 10 Jan 2009 18:31:16 +0000
Pete Verdon d wrote:

Hi,

Currently, my bathroom has a fan which switches along with the light and
stays on on a timer afterwards. Most of the time, this is unnecessary -
if I fill up a glass of water before going to bed I don't need a fan
waking up everyone else in the house.
snip

One, totally orthogonal, thought is to have a heat recovery fan running
all the time. Needs no particular switchgear.

I'm considering one of these:

http://www.bes.co.uk/products/178.asp

R.