The problem of climate change is quite serious and the use of air conditioning during the heat and adds even more carbon dioxide to the atmosphere. Researchers from the Massachusetts Institute of Technology and the University of Hong Kong in the course of experiments with existing films for windows have developed their own, more effective. It remains very transparent up to + 32 ° C, and at higher temperatures it acquires a matte appearance. As a result, up to 70% of the sun’s rays are reflected, lowering the room temperature in the hot season. At the same time, the energy needed to operate the air conditioner is saved. For better thermal insulation, scientists inserted tiny spheres filled with water into the polymeric material of a standard film on the windows. At high temperatures, the spheres begin to shrink, causing the polyfibres to come together. This gives the glass a dull appearance, blocking up to 70% of the incoming heat, but without reducing the light. Such films were tested before, but they did not block heat very well. A team of scientists from MIT and Hong Kong concluded that to improve the effect of the film, water-filled bubbles need to be increased to 500 nanometers to match the infrared wavelength responsible for most solar heating.