In September 2021, Snopes saw social media posts claiming researchers at Purdue University in West Lafayette, Indiana, had invented a paint that received a Guinness World Records title for the being the whitest in existence.
The assertion was accurate.
In a Sept. 20 news release, the university announced the 2022 edition of Guinness World Records features the paint formula developed by mechanical engineering Professor Xiulin Ruan and his graduate students. Additionally, the website for the records indeed lists the Purdue researchers' "barium sulphate paint" as the world's whitest.
But that isn't the paint's only special quality.
The paint made news headlines months earlier in spring 2021, soon after the American Chemical Society published a report written by Ruan's team.
In that publication, as well as an April news release by Purdue, the researchers explained how the white paint reflects up to 98.1% of sunlight, and simultaneously sends infrared heat away from its surface — a process that could help keep buildings cool without so much air conditioning, unlike similarly designed products. (For comparison, other paints that aim to reject heat only reflect 80%-90% of sunlight and do not contain properties to make surfaces cooler than their surroundings, according to the release.)
“If you were to use this paint to cover a roof area of about 1,000 square feet, we estimate that you could get a cooling power of 10 kilowatts. That’s more powerful than the central air conditioners used by most houses,” Ruan said in the April release.
In other words, the paint has the potential to help buildings rely less on air conditioning systems that are responsible for a portion of the world's greenhouse gas emissions, according to the researchers.
The Guinness World Records' website stated:
Such paints are considered to be a potential game-changer for keeping the planet — particularly cities — cooler and reducing electricity use; buildings with a coating of this would need to rely far less on energy-hungry air conditioning. [...]
[The] scientists estimate that it would only require 0.5–1% of Earth’s surface to be coated in this paint (e.g., by painting roofs) to reverse global warming to date.
As of April, Ruan's team was working with a company to produce and sell the paint, according to the BBC.
"I already had an inquiry from a museum that wants to put up a display of our whitest white paint side by side with the blackest black," he told the news outlet.