"Lower costs, greater availability, and the drive to reduce carbon emissions are pushing us toward a tipping point where triple-pane windows start making a lot of economic sense," said Kate Cort, a research economist at PNNL and program manager for ongoing field validation studies of triple-pane windows.

It's no secret that a home's windows can waste a lot of energy. They can leak air, and even the latest models of double-pane windows contribute significantly to energy use and cost in a home. For a new home, windows typically make up about 8% of the exterior surface area but are responsible for half of the heat loss or gain. This passive energy loss makes windows a major contributor to home heating and cooling costs.

Meanwhile, evidence for the energy and cost savings of triple-pane windows has been slowly building for years, since the first prototypes were introduced around 1989. Previous studies have shown that triple-pane windows are more energy efficient than the industry-standard double-pane variety, but market adoption has been slow due to cost and availability.

Those downsides are about to change, said Cort. A new generation of thin triple-pane windows are less expensive and can be more easily retrofitted into existing double-pane frames. As their name implies, triple-pane windows have three panes of glass that create a double-decker sandwich, which gets filled with an inert gas, such as krypton, that provides additional insulating power. These next-generation windows take advantage of economies of scale provided by the same advanced glass manufacturing technology that churns out thin but durable TV and computer screens.