Sometimes, when you get into your car on a cool fall or winter morning, you’ll find a stubborn layer of fog or even frost on the inside of your windows. If your car’s heating system isn’t at its best, it can take a long time to defog your windows.
You can wipe away the fog, but it just keeps coming back until the insides of your windows start to get warm. It’s annoying (especially when you’re late for work), and it’s also dangerous to drive when your windows keep fogging up.
Your windows fog up when water vapour inside your vehicle condenses on the cold glass. Here’s a simple trick that you can use to get rid of that condensation and clear the insides of your windows fast.
The trick is to get cold, dry outside air into your car so here’s what you do. Turn your heater on all the way and set it to Defrost. Also turn on the a/c (in many newer cars, when you select Defrost, the a/c comes on automatically).
The a/c evaporator in your car does a great job of removing moisture from the air. Make sure that the circulation control is set to bring outside air into the car. You want to replace the humid air inside the car with drier outside air. Also crack your windows a bit to let as much cold, dry outside air into your car as possible. Within a couple of minutes, your windows should be fog free and you’ll be able to turn off your a/c and drive your car safely.
If you want to prevent your windows from getting foggy in the first place, you can fill a couple of socks with cat litter and place them in your car – one at the front on the dashboard, and the other at the back. Cat litter is a great absorbent and it will suck the moisture right out of the air in your vehicle.