Researchers at the University of Colorado – Boulder are developing an inexpensive, do-it-yourself coating to retrofit energy-inefficient windows in residential and commercial buildings. They have now received a $4-million boost over three years by the US Department of Energy (DOE). The funding will be used to develop a paintable, infrared-reflective coating that is expected to drastically reduce cooling costs for structures, and help reduce greenhouse gas emissions by minimizing solar heat gains. The award also involves the California Institute of Technology in Pasadena, CA, the Lawrence Berkeley National Laboratory (LBNL) in Berkeley, CA, and Materia Inc., a private company headquartered in Pasadena. Widespread national use of the new window coating promises to reduce the consumption of electricity used for cooling by 35-billion kilowatts, saving a projected $4 billion annually, said CU-Boulder assistant professor Garret Miyake, of the Department of Chemistry and Biochemistry. Miyake, who is also a faculty member of the Materials Science and Engineering (MSE) Program at CU-Boulder, added that the improved energy efficiency would decrease US carbon dioxide emissions by roughly 26-million tons per year, the equivalent of removing 120-million cars from the road. “Our goal is to provide an inexpensive product across a broad marketplace to improve energy inefficient windows and create significant savings for consumers,” Miyake said. The coating consists of polymers that self-assemble into a photonic crystal structure which simultaneously reflects heat and is transparent to visible light. An economic analysis by the team indicates that windows could be retrofitted for about $1.50 per square foot. While infrared-reflective coatings are commercially available and have demonstrated significant energy savings, there are high up-front costs that can deter many potential customers, explained Miyake. Such coatings generally need to be incorporated during manufacturing or installed by professionals. “We will be able to provide an inexpensive paint that can be directly applied to windows by consumers to minimize solar heat transport and improve the energy efficiency of virtually all window types,” he said.