A new “smart” roof coating developed by researchers at Lawrence Berkeley National Laboratory could help homes stay cooler in summer and warmer in winter potentially cutting household electricity consumption by up to 10%.
The experimental material, known as a temperature adaptive radiative coating, or TARC, automatically changes how it releases heat depending on the temperature. Unlike conventional cool roofs, it requires no electricity, sensors, wiring or batteries.
The technology is based on vanadium dioxide, a material whose properties change dramatically at different temperatures. In its natural form, the material switches behaviour at around 67°C, making it impractical for everyday roofing. Researchers added small amounts of tungsten to lower the transition temperature into a range suitable for buildings.
At lower temperatures, the coating releases relatively little heat, helping buildings retain warmth. As temperatures rise its thermal emittance increases sharply, allowing excess heat to escape and helping prevent overheating.
Researchers tested a small TARC panel outdoors at a home in the Berkeley area alongside conventional white and dark roof samples. The coating reflected around 75% of sunlight while changing its heat release behaviour in response to temperature.
Using the results, the team modelled the coating’s performance across 15 different climate zones in the United States. TARC outperformed existing roofing materials in 12 of the 15 regions with particularly strong results in areas experiencing large temperature variations between seasons or between day and night.
The researchers estimate that an average American household could reduce its electricity consumption by as much as 10% using the technology.
The development could address a growing global challenge as demand for air conditioning and cooling places increasing pressure on electricity grids. Conventional cool roofs can reduce summer cooling costs, but their ability to continuously release heat can become a disadvantage during colder months, potentially increasing heating requirements.
By adapting automatically to changing temperatures, TARC could offer a more balanced solution for buildings in regions with both hot summers and cold winters.
However, the technology remains at the research stage. Scientists are now working on larger prototypes and testing how well the coating can withstand weather and long-term outdoor exposure.
Beyond rooftops, researchers believe the temperature responsive material could eventually find applications in areas such as vehicles, satellites, electronic devices, tents and clothing.
The study highlights how advanced materials could help reduce building energy consumption without relying on additional power turning an ordinary roof into a passive system that responds to the changing seasons.