This paint can keep your house cool
What's the story
As global temperatures soar and water scarcity becomes a pressing issue, a team of Australian researchers has come up with an innovative solution: a nanoengineered paint. Developed by Chiara Neto and Ming Chiu from the University of Sydney, the revolutionary coating is designed to reflect most of the incoming sunlight and minimize heat absorption by buildings. The duo's idea was inspired by the urban heat island effect, where cities become hotter due to concrete and rooftops absorbing solar energy.
Start-up journey
Start-up rethinks infrastructure design
The initial research led to the establishment of Dewpoint Innovations in 2022, a start-up with a vision of rethinking infrastructure design. The founders believe that if rooftops across cities could reflect heat and collect water, they could play a major role in solving climate problems. "Our paint will significantly reduce the heat load the sun puts on cities," said Chiu, now CTO at Dewpoint Innovations.
Technology explained
Paint showed solar reflectance of up to 96%
The unique nanomaterials in the paint employ a technique called passive radiative cooling. This method reflects most of Sun's energy and emits heat back into the atmosphere, keeping roof surfaces cooler than surrounding air without consuming energy. In a six-month outdoor trial reported in 2025, Dewpoint's coating showed solar reflectance as high as 96%. This higher reflectivity resulted in less heat absorption, keeping roof surfaces up to six degree Celsius cooler than ambient air and reducing heat transfer into buildings.
Impact assessment
'Tangible tool for climate adaptation'
In a three-month field trial in Sydney in late 2023, Dewpoint's roof paint stayed up to 30 degree Celsius cooler than a standard dark roof. This translated into an estimated reduction of up to 34% in household cooling energy use. Baohua Jia, a nanotech expert at RMIT University, said Dewpoint's roof coating could be "a tangible tool for climate adaptation in dense urban areas."
Water harvesting
Can also harvest water from air
The cooling paint also has the ability to harvest water from the air. This is because a cooler surface encourages moisture in the air to condense on its surface, just like how water forms on a cold glass. In early trials, Dewpoint's system was able to collect 74-liter of water per day from a 200 square meter roof.
Water supply
Supplemental water source
While the paint can't replace a home's full water supply, it can serve as a supplemental source. "It'll help reduce the burden, but it's not the miracle cure," said Dewpoint CEO Perzaan Mehta. The company has found that a minimum relative humidity of roughly 70% is needed for water collection to work efficiently. This makes it ideal for coastal, tropical areas such as Singapore or South America's Amazon Basin.