Double Glazing is when two panes of glass (separated by a layer of air), are used in a home's window.
This provides another layer of insulation for your home, decreasing heat loss through your windows.
In the past, windows were fitted with a single pane of glass, which proved to be a particularly efficient heat conductor. Ongoing research has shown that adding a second pane of glass, with a sealed pocket of air (or gas) in the middle, dramatically reduces the loss of heat through windows.
The requirement for Double Glazed windows in new homes did not become compulsory until 2007, so there are still many NZ homes with inefficient single pane windows. There are a couple of options for double glazing existing windows-
Retrofit Double Glazing
Where an Insulating Glass Unit (IGU) is integrated into current aluminium joinery. Fixed windows only require some of the extrusions replaced, whereas opening windows require a new frame.
Where an existing window has a second pane of glass, or an acrylic sheet, attached on the inside. The gap between the inner and outer pane provides a thermal barrier to help prevent heat loss.