Unconventional Method: Yogurt on Windows Cools Rooms Significantly, Researchers Find

In an effort to combat rising indoor temperatures during heatwaves, a senior lecturer at Loughborough University has proposed an unusual yet potentially effective method: applying yogurt to the exterior of windows.

Dr. Ben Roberts, who lectures on healthy buildings, claims that this technique can reduce indoor room temperatures by up to 3.5 degrees Celsius. His conclusion is based on the results of a month-long experiment conducted at the university. "During the day, we cannot cool our homes sufficiently. This is a serious problem for many people, so we started looking for solutions to block the sun and prevent its rays from entering the house during the day," Dr. Roberts explained.

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During the day, we cannot cool our homes sufficiently. This is a serious problem for many people, so we started looking for solutions to block the sun and prevent its rays from entering the house during the day.

The experiment involved two identical rooms at Loughborough University. One room's windows were coated with yogurt, while the other served as a control. The findings indicated that rooms with yogurt-coated windows maintained an average indoor temperature that was 0.6 degrees Celsius lower than the control room. On particularly hot and sunny days, this difference widened to as much as 3.5 degrees Celsius.

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The yogurt on the glass forms a thin film. Due to its light color, it reflects part of the solar radiation hitting the window. As a result, less heat penetrates the interior through the glass.

Dr. Roberts explained that the yogurt forms a thin film on the glass. Due to its light color, this film reflects a portion of the solar radiation that hits the window, thereby reducing the amount of heat that penetrates into the room. He noted that while the yogurt emits a slight odor for about 30 seconds as it dries, the smell disappears completely once it is fully dry.

The idea reportedly originated from a conversation with Tom Greenhill, author of the "Heatwave Toolkit," who had previously experimented with coating his own windows with yogurt. This method, while unscientific until now, aims to provide a low-cost solution for preventing homes from overheating. The researchers used approximately 10% fat Greek yogurt purchased from a supermarket for their experiment. Dr. Roberts expressed surprise at the method's effectiveness, especially when compared to results using aluminum foil, which achieved a 5–6°C reduction. "This shows the importance of window protection and various solutions for covering them to reduce overheating," he stated, highlighting the potential to reduce heat-related deaths and improve public health and well-being.

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This shows the importance of window protection and various solutions for covering them to reduce overheating. In the summer, we record a significant number of excess deaths due to heat, so if we manage to keep homes cooler, we can reduce the number of such deaths and improve people's health and well-being.