Scientists in the US have created a paint “whiter than the whitest paint currently available”.
Tests conducted by researchers at Purdue University on their “ultra-white” paint showed it reflected more than 98% of sunlight.
That implies, the scientists say, that it could assist fight climate change and save energy.
Painting “cool roofs” white is an energy-saving method already being rolled out in some larger cities.
Commercially prepared white paints reflect between 80% and 90% of sunlight, according to head researcher Prof Xiulin Ruan from Purdue, in West Lafayette, Indiana. “It’s a great deal because every 1% of reflectance you get turns to 10 watts per metre squared less heat from the Sun,” he said.
Could White Paint Help Control Global Warming?
“Cool,” white roofs are seen as a simple, urban climate solution.
In the US, New York has lately covered more than ten million sq ft of rooftops white. The state of California has now updated building codes to encourage cool roofs.
Their advantages are still being investigated, but researches have shown they can decrease energy requirements and create lower ambient temperatures. That has the added advantage of reducing the amount of water used for irrigation in fields.
The new paint comprises a compound called barium sulfate, which is also used to make cosmetics and photo paper.
“We used a very high density of the compound particles,” revealed Prof Ruan. “And we use lots of different sizes of particles because sunlight has different colours at the varying wavelength.”
How much every particle scatters light depends on its size, “so we intentionally used different particle sizes to disseminate each wavelength”.