This article was originally featured on our sister site BUILDER.

Courtesy Alpen

A new window from Alpen High Performance Products achieves an R value previously unheard of in the U.S.

The Zenith series ZR10 double-film fixed picture window insulates nearly as well as some walls, says Alpen CEO Brad Begin. Following certification by the National Fenestration Rating Council (NFRC), the company's Zenith Series ZR10 double-film fixed picture window design was verified to deliver a .10 U-Factor, which equates to an R10 insulating factor, says Begin.

“Achieving R10 performance, which is equivalent to an NFRC U-factor of 0.10, represents a major accomplishment – beyond Alpen as a company and for the fenestration industry at-large,” he says.

The window, the country's first commercially available R10 window, was designed using Lawrence Berkeley National Laboratory simulation tools to optimize design features such as glazing layers, coatings, gas fills and frame design. It rounds out the company’s existing range of Zenith Series 1025 and 925 double-film high-performance window designs, engineered to provide super insulating properties in both heating- and cooling-dominant climates.