Which Air Circulation Mode to Use for Defogging Inside the Car?
2 Answers
When defogging inside the car, use the external air circulation mode to introduce outside air into the car, which helps remove fog faster. Turn on the car's air conditioning cooling function along with external circulation, and set the fan to maximum speed. This can typically clear the fog on the windshield in just over ten seconds. To completely eliminate fog inside the car, use warm air to blow the windshield. Start with external circulation, select the warm air mode and direct the airflow to the front windshield vents. Wait for about five minutes, then switch to internal circulation or turn it off directly. Using warm air for defogging in winter is more comfortable, but it takes longer to remove fog compared to using cold air.
Having driven for many years, I've encountered quite a few issues with fogging inside the car. Fogging mainly occurs when there's too much humidity inside the car, and when there's a significant temperature difference, condensation forms on the windows. In such situations, I always switch to the external circulation mode because it draws in dry air from outside, displacing the humid air inside, and the fog gradually dissipates. Combined with the defogging button on the air conditioning, turning the fan up higher and setting the temperature to a moderate level makes the effect quicker and more noticeable. Never use the internal circulation mode, as it only recirculates the humid air, making the fog worse and even causing slippery roads to become hard to see. For safety, when the fog is heavy, slow down or stop to check if the windows are clean. Regularly cleaning the windows and the air conditioning filter can prevent fogging. In short, develop good habits—don’t panic when fogging occurs, and switching to external circulation is the first choice.
