Double glazing is essentially insulated glazing (IG), a term that many homeowners are probably unfamiliar with since it isn’t used very often. Double glazed windows are windows comprised of two panes of glass within the same frame with a gap between the panes – 6mm to 20mm wide – that can filled with air or a special gas like argon.
Although a relatively new technology, double glazing follows on from previous window technologies such as storm windows, which were mounted either internally or externally and function in a similar way to insulated glazing, and to a lesser extent, sash windows which were prominently found in Georgian and Victorian houses.
Double glazed windows are now a common sight and double glazing can be used on a wide variety of windows. These include awning, casement, sliding and a wide range of other window varieties, with the window frame housing the double glazing made from materials such as a variety of timbers, along with PVC or aluminium.