What to Do When the Windshield Frosts Up with AC On?
2 Answers
There are three solutions to defrost the windshield when the AC is on: 1. Activate the AC defrost mode: If the windshield frost is severe, turn on the heater and adjust it to blow upward toward the windshield to quickly raise the temperature of the front windshield. Press the front windshield defrost button to enter full defrost mode, which will gradually dissipate the frost. 2. Use automotive-specific anti-fog spray: Before applying the anti-fog spray, clean the inside of the front windshield thoroughly, spray an appropriate amount of anti-fog spray, and after it solidifies, wipe it clean with a soft cloth. The anti-fog spray forms a water-repellent layer between water molecules and the inner surface of the glass, keeping the glass surface clean and preventing frost. 3. Use dish soap to prevent fogging: This is an effective method to prevent car window fogging. Simply dilute household dish soap with water at a ratio of 1:6, then wipe the car windows with a soft cloth soaked in the solution. After the dish soap dries, wipe it clean with a dry cloth. This can prevent frost on the front windshield for about 10 days.
As a seasoned driver, I always get a bit worried about visibility when the windshield fogs up with the AC on. I immediately locate the defogger button, usually the one with a windshield symbol, and pressing it automatically directs the airflow to the front glass, clearing the fog super fast. For heavy fog, I increase the fan speed and adjust the temperature to a moderate level—avoiding overly hot air as extreme temperature differences can cause fogging again. When the car is humid, I slightly close the windows to prevent outside moisture from entering. I also make it a habit to open the windows when parked to ventilate and keep the interior air dry. Regularly cleaning the AC filter helps a lot too—clogged filters can reduce airflow efficiency. These small daily routines make driving worry-free and safer. I highly recommend practicing them to get used to the operations.
