Warm edge

A warm edge or thermal spacer is a type of spacer bar used in insulated glazing in windows. It separates the panes of glass in double or triple glazing and seals off the air cavity between each. Modern spacers are generally made from vinyl (uPVC) or high-grade steel which both have better insulation properties than other materials. The resulting spacer system is often referred to as a “warm edge.” In the past, these spacer bars were often made of aluminum which allowed heat transfer through the window which led to both heat loss and condensation.

References