"js.b1" wrote in message
...
As stated, yes, very easy.
Basically they cut a hole in each pane of glass and fit a metal edge
seal around the hole.

Fit a decent fan (Xpelair or Ventaxia) and do not overtighten when
fitting. That way you do not risk damaging the seal or breaking the
thin panes of glass more often than necessary.

If you have not already bought the extractor... Xpelair GX6 are great
for airflow & reliability - leave running overnight in the summer to
pull cool air into the house. Somewhat better is a GX9 which has a
ability with a controller to intake air, making forced intake of cool
air overnight in summer very easy. Xpelair come with two types of
shutter - mechanical "bang-bang" with a pullcord, electronic either by
remote-trimmer (light, humidistat) or pullcord. The electronic shutter
with pullcord is GXC6T which is quite rare and has an adjustable run-
on timer. The mechanical type if tugged too hard can break and the
part is probably £12-20 delivered (not cheap). The electronic pull-
cord type are longer lasting. They use an internal timer so are L+N+E,
there is no external trigger so can be wired with a DP Isolator. Do
not fall into the idiot trap of thinking "it must use a 3-pole
isolator" and switching the Earth, the 3-pole are L1+L2+N with L2
being the trigger from (say) a lighting circuit or humidistat.

Never tried the Humidistat version of the GX6/9 fans - or rather I
did, but it would not turn on. I could not figure out how it sensed
humidity with the vent shut and no means of external humidity being
drawn in, nor could Xpelair tell me how either when I telephoned them
and told me to buy the GXC6T which had the electronic shutter (it's a
wax pellet & spring).

Sadly I must also add that window fans are not as good as cooker hood
extractors, so go for a "proper Brand" 6-inch as the minimum. As a
guide a cheap cooker hood is 220-250m3/hr which is equivalent to a 6-
inch window fan, whereas a good twin-fan cooker hood is 450-550m3/hr
which is equivalent to a 9-inch window fan. Most people having tried a
twin-fan cooker hood would not go back to single, because once you get
beyond about 400m3/hr it eliminates all odour and condensation
problems very quickly indeed.

The only alternative is a dehumifier like an Amber Dry or X-Dry. These
are great in that they a) heat the kitchen b) remove moisture very
effectively even at very low temperatures and c) do not blow all that
heat outside. Unfortunately out of curiosity when I tried one it
proved too slow to prevent chronic steaming up and whilst it retained
the heat in the kitchen it actually got far too hot despite being -4oC
outside with a howling icy wind (last winter). Nice idea, perhaps
someone has tried it for longer or stuck a heat pump on dehumidifier
mode in their kitchen which tend to be extremely powerful :-)

My sincerest thanks for all the information.
I think the best thing to do is ask the DG fitter to fit the fan for me that
way if the glass breaks then it is his responsibility and not mine.
I shall be running the fan from a plug socket about 2 foot from the window
that way I can get around Part P, plus SWMBO will be happy that the wall has
not to be chased out for any cables.
We have a deep fat frier near to the winodw and at the moment, before we
have the new windows fitted, we have an opening light which the wife, bless
her she's 4'8" can't reach, so I thought of the extractor fan idea.
Now off to do some more research..

Thanks again,
Jim