Q: What is an "insulated" window?
A: Newer windows are often referred to as "insulated" because of technology that retards, blocks, or slows the transfer of air through the unit. Most people are familiar with fiberglass or other types of insulation material in a wall cavity. In a window, the "insulation" is a combination of several factors. Most common are windows with at least two panes of glass enclosing a 'dead' airspace between them. The airspace may also be sealed to contain a clear, odorless gas (commonly argon), which is heavier than air and thus an even more effective insulator. Better yet, one or both inside surfaces of the glass can be permanently laminated with a clear coating that further retards thermal transfer and protects the home interior against solar heat gain and damaging ultraviolet rays.