Thermopane

Thermopane insulated window glass was invented by C. D. Haven in the United States in 1930. It consists of two sheets of glass that are bonded together in such a manner that they trap air in the space between them. Often this space is filled with an inert (unreactive) gas which increases the insulating quality of the window.

Glass traps warmth in a building because it allows the short wavelengths of light to pass through it, but prohibits nearly all of the long waves of reflected radiation (heat) from passing back through it.