Clive Long,UK wrote:
Learn from my experience

If you live in flats and are only replacing some of the windows,
insist, really insist, that the dimensions of the new frame are as
close as possible to the existing - so that the new frames do not
stand out like a sore thumb. I guess that UPVC is structurally much,
much weaker than wood or metal hence the UPVC frame needs to be much,
much thicker to support the glazing units. If they are very much
thicker than the other unchanged units, they will look ridiculous.

To my mind nearly all UPVC frames look ridiculous/ugly.

--
Chris Green )