
Double glazing is a window construction method which employs two glass panes that remain separated by a sealed air or gas-filled space (argon or krypton gas typically fills this gap). The space between the panes helps to reduce heat loss and sound transmission when compared to single-pane windows.
The heritage protection of period and listed properties allows for slim-profile double glazing (which measures between 14–16mm) and vacuum insulated glazing (VIG) (that measures 6–8mm) to be installed into original timber frames without any changes to their appearance or functionality.
The system allows buildings to keep their original architectural style while increasing insulation performance and protecting against condensation and drafts and external noise.


