Just been admiring a friend's new kitchen. He commented the extractor wasn't
very good and I suggested he gives some thought to how air is allowed to
enter the kitchen to replace the air that is being taken out.

We got to thinking about why the fan is in the hood - and why isn't it on
the outside at the end of the duct (he has quite a long duct - crossing the
kitchen above the ceiling to get to the outside wall). I guess it makes
things easy from a selling point of view to have everything in one unit -
but we could see advantages in moving the source of noise to the outside.

Any thoughts or experiences of an external extractor fan?

In article ,
"John" writes:
Just been admiring a friend's new kitchen. He commented the extractor wasn't
very good and I suggested he gives some thought to how air is allowed to
enter the kitchen to replace the air that is being taken out.

It may be that the fan isn't suitable for a
long pipe run. You can get hoods with powerful
centrigugal fans designed for driving long pipe
runs, but they're often significantly more
expensive. It could also be that he has used
too small a pipe for a long run.

We got to thinking about why the fan is in the hood - and why isn't it on
the outside at the end of the duct (he has quite a long duct - crossing the
kitchen above the ceiling to get to the outside wall). I guess it makes
things easy from a selling point of view to have everything in one unit -
but we could see advantages in moving the source of noise to the outside.

Any thoughts or experiences of an external extractor fan?

That's normal for commercial grade kitchen extractors.

I built one for a shower room some years back.
It was a 13" brick wall which already had a 3.5"
old boiler flue pipe through the wall, so I built a
waterproof extractor to go on the outside wall. The
inside of the pipe is in the shower cubicle, and just
has a grille. It saved trying to widen the existing
hole, and there's nothing live in the shower cubicle.

http://www.cucumber.demon.co.uk/extractor.jpg

I did have a hunt around for an externally mounted
extractor for this type of scenario, but was rather
surprised to find nothing at the time. In the case
of a kitchen hood extractor, the design would have
to be different, as the fan I used here would clog
with grease. They are usually centrifugal fans with
the motor mounted out of the greasy airflow.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Sat, 3 Jan 2009 18:21:28 -0000, a certain chimpanzee, "John"
randomly hit the keyboard and produced:

Just been admiring a friend's new kitchen. He commented the extractor wasn't
very good

My completely un-scientific rule of thumb for a kitchen extract fan is
that it should be able to hold up two sheets of A4 paper. Switch it
on, then put a couple of sheets of paper under the grille. If it won't
hold them, it's probably not powerful enough.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have you strayed"?

There are a few inline fans that we use that do a great job.
Just fit a grill in a box unit above the hob at one end and a grill on
the outside wall at the other.

Most hoods are manufactured as a compromise as not everyone wants
to(or can) vent to an outside wall, so, for those who just want to put
in a carbon filter, the motor stays in the body of the hood.


Just been admiring a friend's new kitchen. He commented the extractor wasn't
very good and I suggested he gives some thought to how air is allowed to
enter the kitchen to replace the air that is being taken out.

We got to thinking about why the fan is in the hood - and why isn't it on
the outside at the end of the duct (he has quite a long duct - crossing the
kitchen above the ceiling to get to the outside wall). I guess it makes
things easy from a selling point of view to have everything in one unit -
but we could see advantages in moving the source of noise to the outside.

Any thoughts or experiences of an external extractor fan?

http://www.jsmdistribution.co.uk

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