BCO wants some magic words in the spec to justify "how the windows
acheive U-value of what-ever-it-was".
Will the phrase from screwfix description:
"28mm Sealed Units with Pilkington 'K' glass"
be sufficient, or do I need to say "filled with ..." etc ?
He mentioned something about 19mm gas-filled. Is this another way of
acheiving required
U values ?
Cheers,
Simon.