Triple-glazed*, Low-Solar-Gain Low-E Glass, Argon/Krypton Gas

This figure illustrates the performance of a window with a very low heat loss rate low U-factor). In this case there are three glazing layers and two low-E coatings, 1/2" argon gas or 1/4" krypton gas fill between glazings, and low-conductance edge spacers. The middle glazing layer can be glass or suspended plastic film. Some windows use four glazing layers (two glass layers and two suspended plastic films). With this window, both low-E coatings are spectrally selective in order to minimize solar heat gain. This window is best suited for climates with both significant heating and cooling loads.

*Includes Double Glazing with Suspended Film

Note: These values are for the center of glass only. They should only be used to compare the effect of different glazing types, not to compare total window products. Frame choice can drastically affect performance.