we are upvc window manufacturer and exporter .
we generally fill our double glazed product with argon gas for best insulation but i highly recommend you ask before k:1.1 permality low e-coated glasses for best insulation for summer or winter. about normal glass permality without argon gas...
i can help u if you have montage expert in UK. we are in Turkey and manufacturing and exportinf garage roller shutters
it is arround 600 euro but for exact price i need your exact dimensions.