Press the defog button, turn on the air conditioning (A/C), set the temperature to the lowest, and switch to external circulation to defog the windows. Both cold and warm air can be used to defog the car windows, but warm air is slower than cold air. The most effective method is using cold air, which blows dry cold air directly onto the glass, preventing water vapor from condensing on the glass and achieving defogging. The method of using warm air is similar to cold air, but note that warm air should not be used on rainy days as it may initially worsen the fog. Always use external circulation when defogging car windows. The reason for car window fogging: There is a temperature difference between the inside and outside of the car. If the temperatures inside and outside the car are different, the surface with the lower temperature will have a lower saturated vapor pressure than the surrounding environment, causing water vapor to gather on the glass surface and form tiny water droplets, resulting in fog. Methods to defog car windows: For manual air conditioning, open the front window defogging mode, set the fan speed to maximum, turn on the A/C, and adjust the temperature to the lowest. Wait a moment, and the fog on the windows will disappear. Some models are equipped with rear window electric heating and external rearview mirrors; pressing the button will remove the fog in about a minute. For automatic air conditioning, usually just press the one-touch defrost button, set the fan speed to maximum, and turn on external circulation. The fog on the car windows will disappear shortly. Air conditioning cooling: Use the air conditioning's dehumidification function to reduce air humidity and remove fog. In summer, especially when multiple people enter the car without turning on the air conditioning promptly, the exhaled air has high humidity, quickly causing the windshield to fog up. Turning on the air conditioning to blow cold air onto the windshield and using the dehumidification function can quickly remove the fog. If the humidity is too high and the air conditioning is ineffective, slightly opening the window can quickly reduce the humidity inside the car. Combining this with the air conditioning will yield faster results. Air conditioning heating: Use warm air to reduce the temperature difference and remove fog. In winter, blowing warm air onto the glass quickly raises the temperature of the front glass, reducing the temperature difference between the inside and outside surfaces of the window, thereby preventing heavy fogging. However, the rear and side windows heat up more slowly, so it takes longer to remove all the fog. Whether using automatic or manual air conditioning, turning on the air conditioning helps with dehumidification. Avoid setting the air conditioning temperature to the coldest, as prolonged use may cause the outer surface of the windshield to fog up. Applying anti-fog spray for prevention: Spray a small amount of defogging agent on the car windows and wipe it clean to remove dirt and stains. While polishing the glass, a thin transparent protective film forms, effectively preventing water vapor from condensing into fog, especially suitable for cold winters. Alternatives to defogging agents include dish soap, soapy water, glycerin, alcohol, or saline solution. After drying, wipe off excess fibers with chamois or a soft dry cloth, ensuring the windows remain fog-free for several days. Opening windows for air circulation: If the fog inside the car is not heavy, opening the windows on both sides allows air to circulate between the inside and outside, reducing the temperature difference and gradually eliminating the fog. This method works on the same principle as using cold air from the air conditioning. However, this method has obvious drawbacks and cannot be used during rain, snow, on highways, or when the fog is heavy.
