Researchers at Princeton and UCLA have developed a passive mechanism to cool buildings in the summer and warm them in the winter.

In an article published June 27 in the journal Cell Reports Physical Science, they report that by restricting radiant heat flows between buildings and their environment to specific wavelengths, coatings engineered from common materials can achieve energy savings and thermal comfort that goes beyond what traditional building envelopes can achieve.

“With the increase in global temperatures, maintaining habitable buildings has become a global challenge,” said researcher Jyotirmoy Mandal, an assistant professor of civil and environmental engineering at Princeton. “Buildings exchange a majority of heat with their environment as radiation, and by tailoring the optical properties of their envelopes to exploit how radiation behaves in our environment, we can control heat in buildings in new and impactful ways.”