Developed by scientists from RMIT University in Australia, this glass coating is made of vanadium dioxide, is self-regulating and requires no power input. It’s also incredibly thin at 50 to 150 nanometers — a human hair is 1,000 times thicker.

When the temperature dips below 67 degrees, the vanadium dioxide acts as a transparent insulator, trapping heat indoors while also allowing occupants to look out. When the temperature rises above that threshold, however, it fends off infrared solar radiation from the outside by turning to metal.

“Our technology will potentially cut the rising costs of air-conditioning and heating, as well as dramatically reduce the carbon footprint of buildings of all sizes,” said professor Madhu Bhaskaran, the project’s lead scientist. “Solutions to our energy crisis do not come only from using renewables; smarter technology that eliminates energy waste is absolutely vital.”

The journal Scientific Reports – Nature published a paper detailing the research.