In 2009, Dr. Steven Chu, the then-Secretary of Energy, advocated for painting roofs white to reflect sunlight and keep homes cooler. It’s no surprise that Australian researchers are trying to come up with new ways of reducing the sun’s impact on roofs as well.
A team of scientists led by Dr. Angus Gentle and emeritus professor Geoff Smith from the University of Technology Sydney have created the new material they claim helps roofs stay appreciably cooler. Described as a “coated polymer stack,” the material combines polyesters and a silver layer and are suitable for just about any roof.
The scientists, who published their findings in Advanced Science, claim that the new material stayed about 52 degrees Fahrenheit cooler than the modern white roof of a nearby building because it absorbs only three percent of sunlight that falls on it. At the same time, it radiates infrared wavelengths. “We demonstrate for the first time how to make a roof colder than the air temperature around it, even under the most intense summer conditions,” Dr. Smith said in an interview with UTS, adding that cooling a roof below ambient air temperature had until now been “an elusive target.”
It’s a whole lot harder to keep the outside of your home clean than it is the inside. Unless you want to bust out the house daily, the material has to work equally well when coated with dirt and debris from the elements. Clean and coated materials work equally well, according to the scientists.
Reducing the amount of heat the roof absorbs could lead to less air conditioner use, especially during peak hours, said Dr. Smith. This is especially a concern in scorching Australia, where three out of four homes use the appliance to keep cool.
