Originally created for extreme climates, insulated glass units are now widely used in all locations.

Insulated glass units are constructed with two or more panels of glass separated by a desiccant filled aluminum spacer that is hermetically sealed with either polypeptide or silicone. The purpose of the desiccant is to absorb any moisture that may form within the unit. Dry air usually occupies the empty space between the panels. Inert gases such as argon are sometimes added to enhance the insulation of the unit. Different combinations of glass types and colors are used to construct insulated glass units with unique aesthetic and performance properties.