House too hot? Energy bill already too high? This UK professor says smearing yogurt on your windows can cool your home

• A researcher in the UK found applying yogurt to windows can lower a house’s temperature by 6 degrees. The discovery comes as the country faces a massive heatwave, as does the U.S. Greek yogurt was used in the study, with a fat percentage of 10%.

The summer of 2025 is already a scorcher—and we’ve got a long way to go. It’s not just the U.S., either. The UK is experiencing a massive heatwave that has resulted in health alerts across parts of the country. That’s especially problematic as few homes in that country have air conditioning—and it’s resulting in some rather unique solutions.           

A professor at Loughborough University has come up with an especially odd way to cool your home that is a lot more effective than you might imagine: Smear some yogurt on the window.

Dr. Ben Roberts says putting yogurt on the outside of windows can lower the temperature by up to 6.3 degrees (Farenheit). The numbers come following a one-month experiment, where two identical test houses braved the heat—one with yogurt windows, one without.

On average, the yogurt house was one degree (F) cooler, but it saw a difference of 6.3 degrees on “hot and sunny” days. The yogurt results in a film on the windows, which blocks some of the solar radiation, which raises the temperature.

(If you’re thinking of trying to recreate this, Roberts says they used Greek yogurt with a fat percentage of about 10%. He didn’t add, but it seems logical to add that you’ll want to skip the fruit-flavored varieties when doing so.)

Roberts admits he was “quite surprised” when he saw the temperature differences, adding he didn’t think the diary product would be as effective as it was in blocking heat.

Worried about the smell? Roberts says that faded as soon as the yogurt had dried, which took less than a minute. He did not, however, address whether the application of yogurt on the windows attracted more bugs.

This story was originally featured on Fortune.com