How to Deal with Foggy Windshield on Rainy Days?

[DiLila]

Press the defog button, turn on the air conditioning (A/C) switch, set the temperature to the lowest, and turn on the external circulation to remove fog. Both cold and warm air can defog the car windows, but warm air is slower than cold air. The most effective method is to use 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 the same as cold air, but it should be noted that warm air should not be used for defogging on rainy days as it may initially increase fogging. When the car windows fog up, use external circulation. The reason for car window fogging: There is a certain temperature difference between the inside and outside of the car. If the temperatures inside and outside 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: Air Conditioning Cooling: Use the air conditioning's cooling and dehumidifying function to reduce air humidity and remove fog. In summer, especially when multiple people enter the car without turning on the air conditioning in time, the exhaled air has high humidity, and the windshield will fog up quickly. At this time, turn on the air conditioning to blow cold air onto the windshield, using the dehumidifying function to remove the fog quickly. If the humidity is too high and the air conditioning is not effective, slightly open the windows to quickly reduce the humidity inside the car. Of course, combining this with the air conditioning will yield faster results. Air Conditioning Heating: Use the method of reducing the temperature difference to remove fog. In winter, use warm air to blow hot air onto the glass, quickly raising the temperature of the front glass and reducing the temperature difference between the inside and outside surfaces of the window. This can prevent excessive fogging on the windshield in time. However, it should be noted that the rear and side windows heat up slowly, so it takes longer to remove all the fog. Whether the air conditioning is automatic or manual, turning it on helps with dehumidification. Do not set the air conditioning temperature to the coldest position, as this may cause frost to form on the outside of the windshield over time. Spraying Anti-Fog Agents 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 is formed, effectively preventing water vapor from condensing on the glass and forming fog, especially suitable for cold winters. Alternatives to anti-fog agents include dishwashing liquid, soapy water, glycerin, alcohol, or saltwater. After drying, wipe off excess fibers with chamois or a soft dry cloth. This can ensure the car windows remain fog-free for several days. Opening Windows for Airflow: If the fog inside the car is not heavy, you can open the windows on both sides to create airflow between the inside and outside of the car, reducing the temperature difference and gradually eliminating the fog. The principle of this method is the same as using cold air from the air conditioning. The downside of opening windows for airflow is obvious: it cannot be used in rainy or snowy weather, on highways, or when the fog is heavy. Rear Windshield Heating: Most cars have a rear windshield electric heating function. The button positions may vary, but the function is the same. Turn on the windshield heating switch, and the fog on the rear windshield will disappear in about a minute.