Today more than ever, homeowners are replacing their old worn out windows with energy efficient replacement windows.   Poorly insulated windows can attribute to 25 percent of a building's heating and cooling costs.

As a homeowner, it is just as important to know what type of window spacer material is being used on the insulating glass unit as it is to know what type of glass package (or glazing) is going into the window. The type of spacer material in your windows can make or break your investment!

In order to overcome the thermal inefficiency of conventional aluminum window spacers, a new type of spacer product called warm-edge technology has evolved in the window industry. Warm Edge refers to the type of spacer material used to separate the panes of glass (or glazing) in an insulated window unit. If the material conducts less heat or cold than a conventional aluminum spacer at the edge of the glass, it is said to be 'warm-edge.'

Most of these newer window spacers are less conductive and out-perform pure aluminum.   But there's still one small problem -- they all contain some kind of metal, and metal is highly conductive.