The whitest paint in the world was revealed earlier this year and now it has just earned its creators a spot in the Guinness World Records 2022 edition. The paint isn't just for dazzling unsuspecting eyes, it could be a gamechanger in cooling buildings and helping fight climate change.
The reflective paint has the ability to reflect back 98.1 percent of solar radiation. It is so reflective that it makes whatever it's painted on much cooler than its surrounding. In a test, a building with a 93 square-meter (1,000 square-foot) roof coated with the paint would receive a cooling power of 10 kilowatts. That’s better than air conditioning used in most houses.
The paint, whose properties are detailed in the journal ACS Applied Materials & Interfaces, uses barium sulfate, a substance used commercially in paper and cosmetics. The new paint came just months after the creation of an ultra-white paint revealed last October that could reflect 95.5 percent of solar radiation. These ultra-white paints are considered the opposite of vantablack, which absorbs 99.9 percent of light.
“In our experiment, the new paint doubles the cooling power of the previous one,” senior author Professor Xiulin Ruan from Purdue University previously told IFLScience.
One exciting test demonstrated that even during the strong sunlight noon hours material covered in the new ultra-white paint was 4.4°C (8°F) cooler than ambient temperatures. It was even better at night, when the material kept a temperature of 10.5°C (19°F) below the surrounding areas.
The whitest white paint square seen with a normal camera (left) and in infrared (right). The infrared shows the temperature difference with the whitest paint cooling not only itself but also the board it is attached to. Image Credit: Purdue University/joseph peoples
“Conventional air conditioners consume power that is often from burning fossil fuel. Meanwhile, while they move the heat from inside of a house to the outside, they turn the electricity into heat and leave even more heat to the ambient and earth, further causing a heat island effect and warming up the Earth,” Professor Ruan told IFLScience.
“In contrast, our paint does not consume any power, and directly sends off all the heat to the deep space, hence helping cooling down the Earth. According to a previous model, painting 0.5-1% of the Earth's surface (roofs, roads, cars, unused land, etc) with our paint will stop the warming trend.”
Painting many human made-structures would be a great way to fight the climate crisis in multiple ways, both in passively cooling and reducing the reliance on electric air conditioning. The paint is not yet available commercially but its composition is compatible with commercial paint processes and can handle being outdoors. The scientists are working with a commercial company to scale up the paint production and put it on the market.
