I discovered this trick during a brutal heatwave earlier this summer. My air conditioner gave out, it was over 100 degrees outside and humid as ever, and I was desperate. Then I remembered seeing something online (maybe on Reddit!) about putting a frozen water bottle in front of a fan, so I gave it a shot — and to my surprise, it actually worked.
How a Frozen Water Bottle Can Create DIY Air Conditioning
The fan (I usually use this one because it’s easy to move around, but people online say it works with a full-sized fan, too!) pushes air past the frozen bottle, which cools the airflow slightly before it hits you. It’s a simple version of evaporative cooling, which the U.S. Department of Energy recommends as a low-effort way to stay comfortable in hot weather. This trick technically uses conduction instead of evaporation, but the result is the same: cooler air, with no extra tech required. Plus, my mini fan definitely uses less energy than my window air conditioner did!
It’s way more effective than putting a bowl of ice in front of a fan, another trick circulating social media. The ice tends to melt quickly and usually ends in a puddle. A frozen water bottle lasts longer, doesn’t make a mess, and is easy to rotate throughout the day. I try to keep a few in the freezer so one’s always ready all summer long.
How I Make This Trick Work Even Harder
BPA-free reusable plastic bottles are your best bet, as they’re freezer-safe, easy to clean, and hold up well through repeated use. If you’re trying to lean away from plastics, PATH metal water bottles are reusable and work great for this hack, too. I’ve also used standard disposable water bottles (as pictured) when I’m in a pinch, and they work too. Just make sure to leave some space in every type of water bottle at the top so they don’t split when the water expands.
Another tip: Skip glass entirely. Even if it says freezer-safe, it’s not worth the risk. Frozen water puts pressure on the container, and glass can crack or even shatter once it’s frozen solid.
Yet another addition people swear by for elevating this trick, as suggested by WikiHow, is adding three tablespoons of salt to each bottle before freezing. It lowers the freezing point of the water, which helps it stay colder for longer. You don’t have to do this, but it does make a difference. The site also shares other DIY options, but if you just want something quick and low-maintenance, this version is the easiest and most useful.
A Few Quick Tips and Reminders
- Always fill the bottles about three-quarters of the way to leave room for expansion.
- Don’t use glass. It can crack or shatter in the freezer.
- Set the bottle a few inches in front of your fan, and place it on a towel or tray to catch condensation.
- If you’re adding salt, shake the bottle before freezing so it dissolves evenly.
- Once it melts, just refreeze it and swap in the next one.
The bottom line is this: This is an easy, low-effort hack that actually helps when your fan alone isn’t cutting it in the summer heat. Of course, it won’t replace an air conditioner, but if you’re looking for a way to cool off fast without spending money or making a mess, this is one trick worth keeping in your back pocket (and your freezer).
Would you try this trick? Let us know in the comments below!