It\u2019s nearly winter in the Northern hemisphere. For many that means drafty windows that waste energy and keep you from being cozy inside your home. Some turn to clear plastic shrink-wrap insulation kits.<\/p>\n
But researchers from the University of Colorado Boulder have a more high-tech, long-lasting solution for insulating windows without obstructing the view. They have made a material that lets 99% of light through while blocking 10 times as much heat as conventional windows.<\/p>\n
The researchers can make the material as flexible square-meter-sized films that could be applied to existing windows, as well as slabs that are multiple centimeters thick made at the square-meter scale. The durable material should last for 20 years, the team says.<\/p>\n
Windows increase the energy use of the built environment. Buildings today consume about 40% of all energy generated worldwide. And over a quarter of a building\u2019s energy is lost through today\u2019s glass windows. In the winter they let heat out, while in the summer they let the sun\u2019s heat in. \u201cTo block heat exchange, you can put a lot of insulation in your walls, but windows need to be transparent,\u201d said Ivan Smalyukh, a professor of physics at CU Boulder. \u201cFinding insulators that are transparent is really challenging.\u201d<\/p>\n
Researchers have made smart windows<\/a> that change their optical properties<\/a> to offer energy efficiency. To keep things transparent, some teams have made clear window coatings from beer waste<\/a> and by layering multiple thin films made of common materials<\/a>.<\/p>\n Smalyukh and his colleagues, meanwhile, have in the past made clear gel films from wood-derived cellulose<\/a> nanofibers. Those aerogels contained randomly distributed air pockets that block heat.<\/p>\n \u00a0<\/p>\n \u00a0<\/p>\n