Why Does the Passenger Side Window Fog Up?

[McMason]

Window fogging occurs simply due to the large temperature difference between the inside and outside of the car. Here are some methods to defog: 1. Use the air conditioning effectively: While driving, you can first turn on the cooling air; if you want a thorough solution, it's best to turn on the heating air before driving or when parked on the roadside until the fog completely disappears. 2. Open windows for air circulation: Based on the principle of fogging, you don't even need to use the air conditioning. Just slightly open both side windows to allow air inside the car to circulate. The advantage of this method is that as the air inside and outside the car circulates, the temperature inside and outside the car will roughly equalize, preventing fogging. 3. Purchase specialized anti-fog products: Anti-fog sprays can be applied to the inside of the windshield and wiped evenly. There are also special anti-fog towels available on the market, which come in dry and wet versions. These towels are more convenient than sprays—just wipe and they work—but their effectiveness is shorter, usually lasting no more than 24 hours.