On a cold, winter morning, you have likely entered your car and been greeted with a foggy windshield. This fog comes from humidity in the air, often produced by the breathing of passengers inside the car. Wiping the windshield with your hand provides only temporary clarity, and trying to drive with a foggy windshield puts you and other drivers at serious risk. There are a variety of natural ways to keep a windshield from fogging up.
Keeping windows clean prevents a film of dirt from forming on your windshield. Dirty windshields and windows can be more conducive to fogging up, as humidity clings to dirt particles on the surface. Wiping the inside of a windshield with an ammonia-based cleaner can help prevent fogging. Complete this task weekly or whenever you notice fog becoming an increasing problem.
Drivers in traditionally frigid regions often install mounted fans on the dashboard. These fans, which face the windshield, keep dry air constantly blowing onto the glass surface. This dry air quickly reduces humidity in the car and reduces the amount of fogging on the windshield. Some of these fans can be plugged into a car's cigarette lighter, while others can be wired into the car's electrical output.
Rolling down a side window as soon as you enter your car can also reduce fogging. This process releases the humidity from inside the car and allows air from the outside to flow across the windshield surface. This method may not be feasible in freezing temperatures, but in moderate weather conditions this is an easy way to minimize fogging.
The recirculation button on your car's dashboard uses the air inside the car and moves it around the interior. Because this air is full of humidity and often the reason for windshield fogging, using the recirculation function will not solve the problem. Turn off the recirculation function and instead use air conditioned or heated air, which is drier and helps eliminate fog.
One unorthodox method for removing fog from a window is to use shampoo. Many types of shampoo contain ammonium, which is a natural cleanser. Use a clean towel to apply a small amount of shampoo to the inside of the windshield. Only a small squirt of shampoo is necessary; using too much will cloud up the inside of the windshield, creating a larger problem than simple fogging.
