What Causes Fogging on Car Windshields?
2 Answers
Reasons for fogging on car windshields: There is a temperature difference between the inside and outside of the car. The outside temperature is low, while the inside temperature is high. The windshield, which separates the inside from the outside, also has a low temperature. The water vapor inside the car condenses into water droplets when it encounters the cold windshield, forming a layer of fog that significantly impairs visibility. On rainy or foggy days, the air humidity is high, and the humidity inside the car is also high, with more water vapor, making it easier for condensation to form fog. Methods to remove fog: Opening the windows can equalize the temperature inside and outside the car, eliminating the temperature difference and preventing fogging. This method is suitable when the weather is not too cold and it is not raining, although the defogging effect is relatively slow.
Windshield fogging is mainly caused by high humidity inside the car and low glass temperature, leading to condensation. I often encounter this issue during my daily commute, especially on rainy days or when there are many passengers. The moisture from breathing inside the car forms fog on the cold glass, which is dangerous as it obstructs visibility and can cause accidents. The solution is to immediately turn on the air conditioning in defog mode or open the windows to allow air circulation. I usually start the car a few minutes early to turn on the heater or apply anti-fog products to the glass as a preventive measure. When the weather turns cold, check for leaks or poor door seals that might let moisture in. Long-term maintenance includes cleaning the windshield to remove oil films and avoid dirt buildup that can absorb moisture and worsen fogging. Remember, safety comes first—slow down and pull over if fogging occurs.
