In article ,
Dave Fawthrop wrote:

But the almost perfect draughtproofing on ours compares very well
with the less than perfect version it replaced. Must save a as
much money as the windows themselves.

I would agree. We had 14 1970-ish steel windows replaced
with d-g, at a fearsome cost. The improvement in morning
comfort is remarkable though...... we don't even know now
how cold it is outside until we open the front door. And
no more condensation on the insides every cold morning.

--
Tony Williams.