A team of MIT researchers has created windows that instantly change color when the sun’s too strong in order to save energy. It’s not magic, it’s a technique that uses electrochromic materials that can go from transparent to nearly black by applying a bit of electricity. Color-changing windows have been created before, but these have a faster response time and can stay dark without being connected to a source of energy. The researchers want to work with investors to make these energy-saving windows common in new homes.