roughbert strong wrote:

There is a french DIY supplier called Lapeyre who sells some rather
nice looking windows. I think that they meet UK building regs, unless
my schoolboy french is letting me down again. I am considering using
them in my new house in UK, has anyone tried them, or had experience
of building regs issues with non-UK sourced windows?

If they are double glazed, you can probably get away with them, but you
may need to get U value certification.

In fact you may be able to use single glazed even - the key issue is
that you approach energy calculations on an ovcerall basis rather than
use the elemental method.

In all cases you will need some idea of their U value though. That the
manufacturer can give you.