On Tue, 18 May 2004 00:58:36 +0100, in uk.d-i-y Martin Angove
strung together this:

one of those rather expensive in-wall heat-exchanger things.

They're not that expensive actually, I usually get them for about
£120ish.

Looks like an ordinary 4" (or 6") from the inside and outside,

6" usually.
--

SJW
A.C.S. Ltd.