How to Solve Fogging on Car Windows?

[Teresa]

If the fog inside the car is not too heavy, opening the windows on both sides will gradually make the fog disappear. Selecting the appropriate air conditioning setting can also help by using the air blown out to defog. Applying anti-fog spray on the inner and outer surfaces of the windows can prevent water vapor from condensing into a fog layer.

[LaCody]

Last time when I was driving my kid to school, the windshield got completely fogged up and it was really frustrating. I figured out a few practical solutions. Turning on the heater works best—after starting the cold engine, just direct the vents toward the windshield and pair it with the AC for better dehumidification. Keep a chamois towel in the car to wipe off the fog in emergencies. The key is to remember to turn on the external air circulation to expel the moisture—using internal circulation on rainy days just makes it harder. I also tried applying a diluted dish soap solution on the inside of the glass; wiping it down kept fog away for a week or two, and it works for side mirrors too. Once, when stuck in traffic and feeling stuffy, I cracked the window slightly for ventilation instead of using the AC to save fuel, and it surprisingly helped prevent fogging. Feel free to give these methods a try.