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Keep Your Car Windows Fog-Free With Just a Potato


We get it — mornings are hectic! Sometimes it feels like there aren’t enough hours in the a.m. to make sure the kids are up, washed, and fed before you scarf down your breakfast and leave for work. The last thing you want to wait for is the windows in your car to defog. And now you don’t have to, because we’ve discovered the best — if unexpected — way to defog car windows, and it involves a potato.

How to Defog Car Windows Without Heat Using a Potato

As crazy as it sounds, using a potato is an easy way to defog car windows without heat. However, you’ll want to try this trick before your windows get foggy in oder for it to work. If you have a dozen spuds sitting in your pantry and you need to use them up before they start sprouting, set aside a few potatoes for your car as well as your husband’s. Now that you have all you need, let’s get started. Here’s how to defog car windows without using heat in five easy steps.

  1. Clean your raw potato and cut it in half.
  2. Rub the cut side of the potato against the car windshield from the outside in long, smooth motions. Wipe off any starch streaks you notice. 
  3. Use the other half of the potato once the first half has dried up. You can cut the tops off the potatoes if both halves are no longer moist. 
  4. Let the potato juice dry. This residue will create a barrier between your windshield and the elements, keeping the glass underneath fog-free.
  5. Toss the used potatoes in the compost pile. 

The reason this trick works so well has to do with science. Layering potato starch on the window creates a barrier that prevents moisture from sticking to the windshield. If no moisture sticks, then visibility is still good. 

Defog Your Car Windows With Cat Litter 

It’s super weird, but it’s true! And it makes sense if you think about it: Just as the litter absorbs moisture in your cat’s litter box, so too will it suck up extra moisture in your car, preventing fog from ever forming on your windows. But before you scatter a bunch of litter all over your dashboard (can you say “cleaning nightmare“?) — follow this simple but important tip: Take one of those old socks that lost its mate long ago but that you’ve been saving in the hopes that the other sock would magically reappear (it’s not coming back, face it) and fill it with a cup or two of cat litter. (Make sure there aren’t any holes in the sock, or you’re going to be facing that aforementioned cleaning nightmare!) Tie the top of the sock closed and place the “litter sachet,” if you will, on your dashboard. Voila! Buh-bye, poor visibility!

How to Defog Car Windows Fast Using Car Controls 

Most cars have a handy defog/defrost button that you can press these days, but if you’re one of the few drivers who doesn’t have one, you might wonder what combination of button-pressing will defog your windows the quickest. Do you blast the cool air or crank up the heat? Should you turn on the AC or use recirculated air? Does cracking the windows help at all?

According to former NASA engineer Mark Rober, the best way to defog car windows fast is to follow these steps:

  1. Turn your defroster fan to the highest setting.
  2. Crank the temperature control to the hottest setting.
  3. Turn on your AC.
  4. Turn off recirculation.
  5. Open your windows a bit.

If you’re like us and want to know the science behind Rober’s trick, you can check out his informative video below. Rober, who now makes YouTube videos, does a great job of explaining the science behind condensation and defogging windows and mirrors in a way that’s easy to understand.

Anti-Fog Products

Don’t have heat but need to clear your foggy car windows fast? There are a few options when it comes to defogging car windows without heat.

Window Anti-Fog Treatment: If you don’t want to worry about fog or frost on your windshield or windows, try a window anti-fog treatment ($11.94, Amazon). Coating all the surfaces you want to keep fog- and frost-free will take a little bit of elbow grease, but it’ll save you a few precious extra minutes every morning. 

Shaving Cream Anti-Fog Treatment: A cheaper anti-fog window treatment option is good old-fashioned shaving cream. Cleaning your windows with shaving cream creates a thin layer that keeps the glass from fogging. Neat, huh?

Silica Gel Dehumidifier: Similar to kitty litter, silica gel dehumidifiers remove excess moisture. You can purchase a silica gel dehumidifier ($8.49, Amazon) for less than $10, but if you’ve been saving the small silica packets that come in shoe boxes and cured meats packages, you can just use those and don’t need to spend a dime!

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