With global warming heating up, and energy costs continually on the rise, engineers and researchers are constantly working on ways to cool the air without warming the planet. Ideas have included painting roads with a paint that reflects sunlight and a paint that produces hydrogen gas for use as fuel. Now, SolCold, a startup based in Herzliya, Israel, has come up with a way to cool buildings without using electricity. The technology is based on the principle of laser cooling, in which firing lasers at certain materials can cool those materials by up to 150°C. Laser cooling works because the materials absorb photons at one frequency, while at the same time emitting higher-frequency photons which carry more energy. In this process energy is lost, which lowers the temperature of the material.