Should the AC be turned on for defogging?
2 Answers
Generally speaking, when using cold air for defogging, the AC should be turned on, while when using warm air for defogging, the AC does not need to be turned on. If the local air is relatively dry, you can also choose not to turn on the AC and instead crack open the car windows to allow air circulation inside the car, reducing the temperature difference between the inside and outside of the car. However, this method can be quite cold in winter. The correct methods for car defogging: 1. In summer: You can turn on the car's defogging mode, set the fan speed to maximum, then turn on the AC and lower the temperature. The fog on the windows will disappear shortly. 2. In winter: You can turn on the warm air, the front windshield defogging function, and the AC. Although warm air defogging is not as fast as cold air, and the fog on the windows may worsen initially when warm air is first turned on, this method provides better defogging results. It prevents secondary fogging while driving and keeps the car warm. When using warm air for defogging in winter, it's best to find a place to stop first, wait for the fog on the windows to dissipate, and then continue driving.
When I encounter foggy windows while driving, I immediately turn on the AC. Once the compressor kicks in, the dehumidifying effect is instant. Especially on rainy days or when there are many passengers in the car during winter, the windshield clears up in just a few seconds. Although using the AC consumes a bit more fuel, safety comes first. Remember to adjust the air vents to the windshield mode and turn on the external circulation for better ventilation. Once, I tried to save fuel by only using the heater, but the fog got thicker and thicker, almost causing a rear-end collision. That scared me so much that I never dare to turn off the AC for defogging again.
