Double vs triple glazing

How do multiple window panes help to reduce heat loss?

Glass

Glass is a relatively good insulator of heat, but due to its transparency thermal energy is easily lost via radiation.

Double glazing

A double-glazed window reflects around 90 per cent of the incident infrared light.

Air leakage between frames Air chamber Heat loss

Heat is lost via conduction, convection and radiation. Tiny gaps between the window frame can also allow warm air to leak out.

Radiation through glazing Conduction through glazing spacers Conduction through window frame

Filled with either dehydrated air or an inert gas such as argon, xenon, or krypton, this helps to reduce heat conduction through the window.

Low-e coating

A thin coating on the outer surfaces of the glass allows natural light to pass through glass while blocking most of the ultraviolet and infrared rays.

Triple glazing

An additional pane improves efficiency, so triple-glazed windows reflect around 97 per cent of the incident infrared light.