The idea of white roofs isn’t a new one. If you’ve ever been to Mykonos, Greece, you’ve seen the famous hillside homes painted white to deflect the scorching sun. But since the weather in Greece is typically hot, this lack of color palette makes no difference in winter, where in colder climes, dark roofs would serve better to retain heat.
Enter MIT graduates, who developed color-changing tiles – white in summer to dispel heat and black in winter to absorb it.
This technology has obvious correlations to seasonal energy savings, and according to U.S. Secretary of Energy Steven Chu, white roofs would also drastically reduce greenhouse gas emissions. The tiles’ creators, a group of 2009 MIT graduates called Thermeleon, entered their project in a school-run energy efficiency competition, where they took home first prize for their ingenuity.
The color-changing process is achieved by trapping a polymer liquid solution between plastic layers, the last one being black, which shows through as long as the temperature is cold enough. When the heat rises to a certain level, the polymer becomes concentrated, producing a white tile.
The tiles are still in the prototype stage and will likely undergo developments before they become saleable. Of particular consideration will be the tiles’ long-term ability to withstand temperature changes and the cost-efficiency of using them in place of traditional tiles.