Nature
PUBLISHED
A strange trend has emerged on the streets of France: windows coated in chalky white gloss. It isn't some quirky fashion statement or an obscure art project, but a low-cost defense against the heatwave currently sautéing Europe.
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Once applied with water, it leaves a blanked-out film that helps to reflect sunlight and heat away from the building.
Builders have long used it to shield buildings during renovation work, but homeowners have now co-opted the trick for themselves. Off the back of the ongoing heat wave, the trend has caught on a little too well.
While stocks last
Panic buying of Blanc de Meudon has reached "toilet roll during the pandemic" levels in recent weeks as people across France rush to stock up in the wake of record-breaking temperatures, according to Le Parisien newspaper.
"My wife went to every DIY store in Auray and couldn't find any,” a shopper called Philippe, who traveled to the next town over to get the product, told Ouest France.
"We'd known about the idea for a while, we talked about it during the last heatwave, but forgot to buy any. Now it's too late! It's sold out everywhere," he added.
Does it actually work?
To our knowledge, there’s no scientific literature on the effectiveness of Blanc de Meudon-ing your windows. However, there is plenty of evidence showing how white paints and pigments can be used to reduce indoor temperatures.
A study in the journal Urban Climate found that reflective white roofs could cool the temperatures inside by up to 1.75 °C (3.15 °F). Another study found it could even lower the surrounding outdoor temperatures by up to 2 °C (3.6 °F).
While Blanc de Meudon might lack the super-reflective properties of a high-gloss industrial white paint, it is cheap, effortless to apply, and just as easy to wash off once the heat breaks, making it an appealing no-brainer for sweltering households.
