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Spreading yogurt on window glass is a reported heat-wave cooling idea, but the available account does not show that it works. British engineer Tom Greenhill says a dried yogurt coating creates a frosted-looking layer that reflects light and heat; no temperature measurements or controlled comparison are provided to verify a cooling effect.
How the yogurt window coating is supposed to work
In an August 27, 2024 report, BGR attributes the idea to British engineer Tom Greenhill. He describes the dried coating as creating a “fritted glass effect”: a frosted-looking surface that, in his account, reflects light and heat instead of allowing them into the home. That is Greenhill’s proposed explanation, not an independently measured optical or thermal result. BGR’s report does not provide solar-reflectance data or indoor temperature readings.
How the method is reportedly applied and removed
BGR says Greenhill applies yogurt to the glass with a generic small paint roller, then lets it dry. The report says the coating can be wiped away with a cloth and water. It also attributes to Greenhill the claims that the dried coating does not smell, does not attract insects, and stays intact unless there is heavy rain.
The account does not specify the yogurt variety, glass preparation, coating thickness, drying time, or precautions for different glazing. It therefore does not establish a repeatable application procedure or suitability for every window. Its reversibility may be relevant to renters, but that does not establish that the coating is safe or appropriate for all glass.
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#1 Best Overall
- Save on energy costs during cold weather months. Duck Max Strength shrink window film is puncture-resistant and two times thicker than standard window kits to create an airtight seal inside your home to block drafts and cold weather
- Easy-to-install roll of shrink film means no measuring needed - once applied, cut film to size
- Tools needed: scissors and hair dryer. For best results apply window films indoors on clean and dry surfaces, including painted or finished wood, aluminum or vinyl
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- Window Kit includes 1, 62" x 210" roll of shrink film and 1, 0.5" x 84' foot roll of tape; Can insulate up to 5 standard sized 3' x 5' windows
Does it actually cool a home?
The available report is anecdotal. It gives no measured change in room temperature, comparison with an untreated window, energy savings, or study citation. Greenhill’s claim that the coating reflects heat is not enough to determine whether it meaningfully cools a room, how much it might help, or whether the effect varies by window orientation. The headline claim that it works is stronger than the evidence presented.
For homeowners or renters deciding whether to try it, the key distinction is between a reported idea and a demonstrated result: the account describes an application and cleanup, but does not establish cooling performance. It also does not compare the method’s cost or reversibility with other cooling options.
Quick Recap
Best Value
- Save on energy costs during cold weather months. Duck Max Strength shrink window film is puncture-resistant and two times thicker than standard window kits to create an airtight seal inside your home to block drafts and cold weather
- Easy-to-install roll of shrink film means no measuring needed - once applied, cut film to size
- Tools needed: scissors and hair dryer. For best results apply window films indoors on clean and dry surfaces, including painted or finished wood, aluminum or vinyl
- After installation, crystal clear and transparent window film is easy to see through. Once season is over, the window kit removes easily
- Window Kit includes 2, 62" x 210" roll of shrink film and 2, 0.5" x 54' foot rolls of tape; Can insulate up to 10 standard sized 3' x 5' windows
Rank #4
- Save on energy costs during cold weather months. This rolled window kit creates an airtight seal inside your home to block drafts and cold weather
- Easy-to-install roll of shrink film means no measuring needed - once applied, cut film to size
- Tools needed: scissors and hair dryer. For best results apply window films indoors on clean and dry surfaces, including painted or finished wood, aluminum or vinyl
- After installation, crystal clear and transparent window film is easy to see through. Once season is over, the window kit removes easily
- Window Kit includes 3, 62" x 210" rolls of shrink film and 3, 0.5" x 54' foot rolls of tape; Can insulate up to 15 standard sized 3' x 5' windows
Rank #3
- This product adds a great value
- Product is highly durable and very easy to use
- This product is manufactured in China
- If you want to open your windows in the warmer months, you'll need to take it off. Otherwise, sunlight and normal stress can also make the tape fail eventually. For a good seal, it's probably best to re-apply them every year.
Rank #2
- Designed for interior use on windows
- Accommodates up to 4 standard sized windows
- Shrinks with hair dryer and applies with included double-faced tape
- Each sheet measures 62 in. L x 42 in. W
- Helps R-value increase up to 90%
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