Fiberglass WindowsFrom Serious Materials

Serious Materials

The maker's fiberglass windows have insulation ratings of R-7, R-9, and R-11. The R-11 windows, in the 1125 series, exceed Energy Star requirements by 300 percent, the maker says, and include xenon gas fill, a triple suspended-film glass package, and a foam-insulated fiberglass frame. 800-797-8159. www.seriouswindows.com.

• R11 Spec Sheet
• R9 Spec Sheet
• R7 Spec Sheet