Energy-Saving Windows Getting Smarter, Cheaper

The US Department of Energy's National Renewable Energy Laboratory (NREL) scientists are developing an insulating window film that "Preserves the view while increasing occupants' comfort and saving energy," according to an NREL press release. The film incorporates nanometer- to micrometer-sized vacuum capsules that can be applied like conventional low-e window tinting films. "Early estimates indicate that a millimeter-thick layer results in clear insulation with values equivalent to R-20, which is equal to standard wall insulations," the release says, adding that: "The window film could reduce building energy use by as much as 33%, resulting in a payback period of less than a year while saving energy and reducing greenhouse gas emissions."