Double glazing considerably these windows
DA14 have two panes of glass, CM3 N11 instead of the traditional single
Window repair pane. A layer of gas,
da14 generally argon, [[
https://cortexofscience.org/groups/how-installing-new-windows-can-help-with-home-improvement/ DA14]] or
AL4 air is between 2 panes and
al8 behaves a good insulator.