Which air circulation mode to use when car windows fog up?
4 Answers
When car windows fog up, you should use the external air circulation mode. The fastest and most effective method when noticing fog on the windshield is to first adjust the air conditioning vents to the front windshield, turn on the AC cooling function, and activate external circulation. Using maximum fan speed, it typically takes just about ten seconds to quickly dissipate the fog on the windows. Generally, car air conditioning systems come equipped with two defogging function buttons: front window defogging and rear window heating. Here's relevant information: 1. Front window defogging: This function directs air conditioning airflow to the front windshield to reduce temperature differences on both sides of the glass for defogging. 2. Rear window heating: When the rear window fogs up, the rear window heating function can evaporate the moisture to achieve defogging.
Previously, when my car windows fogged up while driving and obstructed my view, I immediately turned on the air conditioning's external circulation mode. The fog cleared up surprisingly fast. The reason is that the external circulation draws in fresh, dry air from outside and blows out the humid air inside, naturally reducing the fog. If you use internal circulation, the humidity inside the car keeps recirculating, which can worsen the fogging. I also used the defrost button, directing the airflow toward the windshield and setting the temperature to medium, making defogging more efficient. If your car has automatic air conditioning, just press AUTO, and it will adjust the airflow and temperature automatically. Remember to clean your windows regularly to remove grease and dust, which can also help prevent fogging. Safety is crucial—when fogging occurs, avoid switching to internal circulation and keep the external circulation mode on for a more secure drive.
I take the issue of window fogging very seriously from a safety perspective. When fogging occurs, it's essential to turn on the external air circulation because it introduces dry air from outside, directly replacing the humid air inside the car, allowing the fog to dissipate quickly. Never use the internal air circulation as it recirculates moisture and worsens the situation. In practical driving, I recommend combining it with the air conditioning's dehumidification function—adjusting the temperature lower or higher is fine, but the key is to direct the airflow toward the glass. Situations like significant temperature differences or rainy days are prone to fogging, so maintaining the air conditioning system in good working condition is crucial. In my daily driving, I often check the fan settings to ensure the external circulation mode is activated. If the car has new features, using the defogging mode can automate the process. Remember this: when fogging occurs, don’t hesitate—quickly turn on the external air circulation.
I think the cause of fogging is simple—condensation forms due to temperature differences and humidity. In this case, turning on the external air circulation is most effective, as it brings in dry air to quickly dehumidify. Internal circulation isn't suitable, as it worsens the problem. Whenever I encounter fogging while driving, I always choose external air circulation, paired with the AC's cold or warm air blowing on the windshield for immediate results. If you have automatic AC, just press the AUTO button to let it handle it automatically. By the way, keeping the windows cleaner can reduce fogging frequency—just wipe the interior with a cloth. In short, don't panic when fogging occurs; turning on external air circulation will stabilize the situation.
