Vacuum-Insluated Glass Windows

Every contractor knows that windows account for the biggest heat loss in a home. They ae also the reason for heat entering a home in hot areas. The main culprit for this heat movement in even the most advanced window systems is convection.

Heat travels through radiation, conduction and convection. Radiated heat goes one way. Simply put, when you stand in front of an electric heater you are warm. When you move away you are not. Conduction is when you fill up a cold glass with steaming hot water and in 120 seconds you cant hold the glass because the heat conducts through the glass.

Convection works on air currents. With a normal double-pane window the hot surface of the inside glass and the cold surface of the outside one causes air currents within the window which, in cold climates, serves to transfer heat outside quicker. In effect, it is a miniature weather system. Heavy gases inserted in between the panes like argon and krypton slow the currents down but do not stop it.

Window manufacturers are now looking to the thermos bottle for help. By taking all the air out of the space between the glass panes this prevents any currents and the air stays dead.

To counter the exterior pressures small spacers are put in between the panes.

In terms of heat retention this system puts a standard double-pane window with low emissivity coatings in the league of a 2 X 4 wall. Now, can you imaging what the insulating qualities would be with a triple-pane, vacuum-insulated, low emissivity glass with an inner plastic pane as a thermal break?