In article ,
Romanise writes:
Instead through wall, thinking to put the exhaust piping of Air-
Conditioner (http://www.ebuyer.com/product/128101) in the chimney
vent.

My flat is on the ground floor with two more floors above me.

I understand that hot exhaust will not fall back in my flat and I do
not need to do any packing in the chimney vent.

You might -- the aircon's of that type generate negative
pressure in the room.

Which brings me to the second point -- they don't work
very well. All that air you are chucking up the chimney
(or whatever route to get it outside) has to be replaced
by air entering the house, and that brings heat in with
it. The air conditioner will spend much energy fighting
with itself over this, and not so much on reducing the
temperature for you.

If the aircon has a separate air inlet and air path for
the air which is exhausted, connect that inlet to the
outside too (separately and well away from the exhaust).
That will prevent the aircon unit drawing warm air in from
the outside to heat your rooms. Not many aircons of this
type do have separate air inlets though.

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