Low heat emission (Low-E) glass is a feature in the windows of many of the business and residential buildings in the United States. According to the U.S. Office of Energy Efficiency and Renewable Energy (EERE), these energy efficient windows can be found in 80 percent of homes and 50 percent of commercial buildings.
However, as popular as these Low-E windows are for keeping the heat out of living and work spaces, there’s a potential energy feature that remains largely untapped and the National Renewable Energy Laboratory (NREL) might just have the technology to realize it.
Researchers from NREL have developed a prototype photovoltaic (solar powered) smart window that can keep heat out of buildings while, at the same time, providing solar energy. The smart windows, built from the energy-harvesting material perovskite, are thermochromic — meaning they can change color from clear to tinted in response to heat. “There are thermochromic technologies out there but nothing that actually converts that energy into electricity,” NREL scientist Lance Wheeler said in a press release.