Double glazed glass consist of two panes of glass separated by a spacer around the edges and sealed to the perimeter, in factory controlled conditions.
The spacer contains a desiccant which eliminates moisture vapor in the cavity.
Double glazed glass units are available in many combinations, and the space between the glass panes can be filled with air or gas.
The trapped air/gas in the gap is an insulator – it does not stop heat being conducted from the inner pane to the outer pane – but it does slow heat transfer by conduction down a lot! The gap is too narrow to allow the air to circulate easily. This therefore also reduces the rate of heat transfer by convection.
Double Glazing has a major impact on the energy efficiency of the building envelope. Poorly designed windows, can make your home too hot or too cold. If designed correctly, they’ll help maintain year-round comfort, reducing or eliminating the need for artificial heating and cooling.