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When you’re trying to keeping your home cool in record hot weather, all the fans, portable AC units and central air conditioning you may be running can rack up an energy bill that’s the equivalent of a small fortune.
Like all good life hacks worthy of viral fame, TikTok brought to our attention a cost-effective solution that can help keep your home more temperate and maximize the effectiveness of your current cooling systems: temporarily applying reflective insulation to your windows.
Many TikTokers credit this trick with lowering the temperature in rooms — especially those that have a lot of windows or are on upper floors of their homes — but I was curious about the science behind these claims.
Joe Pesce, an astrophysicist at the National Science Foundation, explained to HuffPost by email that such window coverings work by blocking infrared radiation, which is the wavelength that we experience as heat from the sun.
“Visible light and infrared pass through most window material (as does some ultraviolet). When infrared passes through, it heats the surfaces inside our house, and then that heat radiates back off the surface – but at a wavelength that doesn’t pass [back] through glass,” Pesce said.
He said that these infrared photons that get trapped indoors are what contribute to heating your home. But if they are effectively blocked in the first place, that will help prevent interior spaces from heating up and lower the energy requirement to cool it.
Of course, this isn’t a completely new innovation. My own grandmother would often line her windows with aluminum foil in summer. The reflective material that’s hyped on TikTok, however, boasts the added element of insulation that also helps keep cool air in.
Pesce can’t speak to any specific brand or window covering in particular, but we found that Amazon’s highest-rated option uses a closed cell polyethylene foam core, rather than bubbles, to offer even greater insulating capability. The retailer says both sides of the humidity- and water-resistant insulation material reflect 95% of radiant energy, and the roll is easy to cut and can be installed quickly using something like double-sided tape. It’s also available in rolls of several dimensions to accommodate windows of all sizes.
People on TikTok have used this particular insulation on their windows for the purpose of home cooling and with great success, too. You can read some of the Amazon reviews below or go ahead and grab a roll for yourself.
Promising Amazon reviews:
″I should have done this YEARS ago! We live in Southeast Louisiana. The majority of the back of our home is glass windows. Our home was anywhere between 74 and 80+ degrees everyday between 2pm and the sun setting. Since putting this on the windows, the temp hasn’t been above 70!!!! I may pass out flyers!!!! My home may look like a spaceship or something off of Star Trek, but I am able to cook in my kitchen without sweating! And the central unit isn’t running ALL DAY AND NIGHT anymore! The product width is one inch less than the description, other than that, no complaints whatsoever.”—Amazon customer
“I purchased this product to help reduce the heat in my dining room. I measured and cut the length I wanted and then applied [it] to my windows. I immediately could tell the difference. I am a happy camper. Thank you.” — Sally Longoria
“I bought [this] for my apartment so that I can keep my home cooled a lot easier and to see if my energy bill would go down. This really helped because it has been so hot in the New Orleans area lately. My bill went down a bit and the strain on my unit hasn’t been as much since before getting this product. I definitely recommend it. If you want your energy bill to drop, use this reflector.” — Denise Marie Richard
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