How to Deal with Foggy Side Windows in a Car?

[VonKayden]

Press the defog button, turn on the air conditioning (A/C) switch, set the temperature to the lowest, and switch to external circulation to defog. Both cold and warm air can be used to defog 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 the purpose of defogging. The method of using warm air to defog is the same as using 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 car windows fog up, external circulation should be turned on. 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 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 droplets, resulting in fogging. Methods to defog car windows: 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 and the air conditioning is not turned on promptly, the high humidity of exhaled air can quickly cause the windshield to fog up. At this time, turn on the air conditioning and blow cold air onto the windshield to use the dehumidification function, which can remove fog from the windshield quickly. However, if the humidity is too high and the air conditioning is not effective, slightly opening a window can quickly reduce the humidity inside the car. Of course, combining this with the air conditioning will yield faster results. Air Conditioning Warm Air: Use the method of reducing the temperature difference to remove fog. In winter, blowing warm air onto the glass can quickly raise the temperature of the windshield, reducing the temperature difference between the inside and outside surfaces of the window, thereby preventing heavy fogging on the windshield. However, it should be noted that the rear and side windows heat up more slowly, so it takes longer to remove all the fog. Whether the air conditioning is automatic or manual, turning it on helps with dehumidification. The temperature control should not be set to the coldest position, as this can cause the outer surface of the windshield to fog up over time. Spraying Anti-Fog Agents for Prevention: Spray a small amount of defogging agent onto the car windows and wipe it clean to remove dirt and stains from the glass. While polishing the glass, a thin transparent protective film is formed, which effectively prevents water vapor from condensing on the glass and forming fog, especially suitable for cold winters. Alternatives to defogging agents include dishwashing liquid, soapy water, glycerin, alcohol, or saline solution. After applying and letting it dry, use a chamois or soft dry cloth to wipe off excess fibers, which can keep the car windows fog-free for several days. Opening Windows for Airflow: If the fog inside the car is not heavy, you can open the side windows to allow air to flow 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 very obvious—it cannot be used during rain or snow, on highways, or when the fog is heavy.