Should You Use Cold or Hot Air to Defog Your Vehicle?
2 Answers
Both warm and cold air can be used to defog a vehicle, but cold air works faster, though it may cause fogging to recur. Here are the methods for using both types of air: 1. Using cold air to defog: Turn on the air conditioning's cold air, press the A/C button, adjust the vents to blow toward the windshield, set the fan speed to maximum, and switch the air circulation mode to external circulation. This allows air exchange between the inside and outside of the vehicle, reducing the temperature difference and making it harder for fog to form, thus effectively eliminating it. 2. Using warm air to defog: Start by turning on external circulation, wait a few minutes, then switch to internal circulation mode. In winter, using warm air to defog is more comfortable and also prevents the windshield from fogging up again.
When it comes to defogging the car, after driving for over a decade, my experience is that both cold and warm air have their advantages. In winter, I prefer using warm air—it gradually heats up the interior and effectively reduces fog buildup, especially when humidity is high; blowing warm air dries the windshield well. But in summer or when fog suddenly appears in the morning, cold air defogs super quickly—just press the button, and it clears up in minutes. Also, pay attention to the air circulation mode: using the external circulation to bring in fresh air helps prevent moisture buildup, while internal circulation is better suited for dry environments. For safety, don’t panic when fog forms—first slow down and turn on the hazard lights, then adjust the AC. My personal habit is to briefly use cold air for quick defogging before switching to warm air for comfort, avoiding temperature differences that cause fogging. In short, adapt flexibly based on the weather, with safety as the top priority.
