As global warming continues, people tend to switch on fans or air conditioners during hot weather. But the more we use electrical appliances, the more energy we consume and carbon dioxide we produce. With continuous breakthroughs in electricity-free cooling, City University of Hong Kong (CityUHK) recently developed a new infrared-transparent aerogel that boosts the cooling performance of subambient daytime radiative cooling materials by up to 5.2°C. The findings were published in Energy & Environmental Science.