Magnified cross-view of the thin iWindow casement before it is attached to an existing window frame.

Serious Materials announced today that its proprietary system for retrofitting windows for thermal efficiency--a system that attracted attention during the Empire State Building's recent makeover--is now available for commercial buildings.

The company gained recognition for developing a system to overhaul and improve the efficiency of the Empire State Building's 6,514 windows as part of the iconic skyscraper's $20 million refresh. The window retrofit was done with no visual change whatsoever to the exterior of the building. Most of the original 26,000 panes of glass were reused, and the changes to each window casement were done right on the premises.

Out of that experience, Serious Materials has now launched the iWindow product for commercial properties. It's essentially a thin window frame containing SeriousGlass that can be installed from inside a building onto an existing window casement in about 20 minutes. Though pricing is particular to each project, Serious Materials estimates that the cost averages about $20 per square foot of glass retrofitted.

The SeriousGlass itself is a superinsulating fiberglass containing "spectrally selective suspended film systems that create air chambers" and offer insulation equivalent to that of triple pane glass, according to Serious Materials. It allows for high light transmission and 99.5+ percent UV blockage, the company says.

"iWindow increases the thermal performance of single- or dual-pane windows, improving full-frame R-value from R-0.8 up to R-3.9 (U-factor 1.2 to 0.25) and center of glass R-value from R-1.0 up to R-7.2 (U-factor of 1.0 to 0.14)," Serious Materials said in a statement.

To put it in lay terms, the company estimates that the iWindow system can increase the thermal performance of a window by up to four times, and in winter increase the interior temperature of a window's surface by up to 22 degrees Fahrenheit.