In article ,
Peter Scott wrote:
Take care. If you have hardwood you might well succeed but from bitter
experience softwood frames do not seal well enough. If you ask unit
makers they will advise you not to try. The units will mist up after a
while even if you paint regularly. I'm now having to think about
replacing all windows for this reason.

Sounds to me like the DG units were too rigidly mounted - the timber
frames move with the seasons so the units have to be fixed in such a way
as to allow this.

--
*The e-mail of the species is more deadly than the mail *

Dave Plowman London SW
To e-mail, change noise into sound.