Spray-on coating rocks. First it was Neverwet. Now, a team of researchers are working on smart windows, which will use electrical currents to stop heat and light from passing through your windows. The invention could save us billions of dollars in energy costs.

Announced in a study in Nature, the tech comes from Molecular Foundry, a Berkeley-based lab that focuses on topics relating to smart energy. The director of Foundry - Delia Milliron was awarded a $3 million grant to work on developing an "electrochromic" window coating that could stop light and heat without using any shades.

The coating demonstrated stopped heat and light and the tech behind it is rather complicated. The windows are coated in nanocrystals of indium tin oxide. When a negative charge is passed, the nanocrystals absorb infrared heat. A stronger negative charge changes the color to block out visible light.

Wired reports that Milliron and her team are already in process of bringing the technology to market. Check out the video below: [Wired]