How to Remove Fog from Glass?

[OEllie]

There are several methods to remove fog from glass: 1. Detergent-based anti-fogging: Detergents can disrupt the attraction between water molecules, reducing their surface tension and allowing water molecules to evenly distribute on the treated glass surface, forming a water film. You can use soap or dishwashing liquid for this purpose and wipe it off with a paper towel. 2. Air conditioning cooling defogging: In summer, fogging on car windows can be caused by low temperature or high air humidity. You can turn on the air conditioning and direct cold air towards the windshield, utilizing the dehumidification function of the air conditioning to remove fog from the windshield. 3. Using external circulation when windows cannot be opened: Turn on external circulation for defogging. The correct vent position should be able to blow air towards both the windshield and the footwell, or just towards the windshield.

[DakotaLynn]

I have a lot of experience with this issue. Fogging mainly occurs due to the temperature difference between the inside and outside of the glass, combined with high humidity inside the car. The simplest solution is to turn on the air conditioning, set the fan to high, and direct the airflow towards the windshield. Make sure to press the A/C button to activate the dehumidification function—this should clear the fog in about 20 seconds. In winter, you can switch to warm air, though initially, the fogging might worsen until the warm air heats up the glass. It's best to turn on the warm air a few minutes before driving to preheat the glass. Additionally, having too many passengers in the car can accelerate fogging, so slightly opening the windows for ventilation helps a lot. To prevent fogging, you can wipe the inside of the glass with soapy water, let it dry, and then polish it with a dry cloth—this can last for two to three days. If fog appears while driving, never wipe it with a towel, as it’s too dangerous.

[MargaretFitz]

The key to defogging is to reduce the humidity inside the car. Start the car and immediately turn on the external air circulation, adjusting the vents to direct airflow toward the windshield. For manual air conditioning, turn the temperature knob to the red zone to activate warm air, while for automatic air conditioning, simply press the windshield defogging button for convenience. Remember to turn on the A/C switch, as the compressor needs to work to dehumidify. On rainy days when the temperature isn't low enough, using cold air to defog can be faster. Another trick is to set the air conditioning to the lowest temperature and turn on the highest fan speed for defogging—this works much faster than using warm air, though it can be a bit chilly. Placing a pack of desiccant in the car or regularly cleaning water accumulation from floor mats can prevent moisture buildup. For long drives, it's best to periodically switch between internal and external air circulation for ventilation.

[DeEmilia]

When I encounter fogging, I immediately turn on the air conditioner and blow cold air directly onto the glass, and the fog disappears in three seconds. In winter, I wait for the water temperature to rise and then blow warm air onto the glass, and the fog will disappear in about two minutes. Spraying anti-fogging agent before driving works exceptionally well, creating a lotus leaf effect that causes water droplets to flow away directly, lasting longer than soapy water. Another emergency solution is to crack open the window slightly to allow air circulation. Remember to turn off devices like car humidifiers. The worst thing to do when fogging occurs is to wipe it with your sleeve, as it affects driving safety and leaves marks. Applying rain repellent on the outside of the windows can also prevent rainwater from sticking, improving visibility in rainy conditions.

[Keith]

There are actually three scenarios for the fastest defogging methods. In summer when the outside temperature is high and fogging occurs, turn on the AC + cold air and direct it toward the windshield. In winter when fogging occurs inside the car, first switch to external circulation and use warm air to blow on the windshield. On rainy days when the inside and outside temperatures are similar, turning on the AC for dehumidification is more effective. It's crucial not to block the air vents under the windshield with piled-up items. Once, I noticed frequent fogging because the floor mats weren’t completely dry after washing—later, placing a few packets of tea leaves in the shoe box surprisingly improved dehumidification. Additionally, when using hot air to defog, it’s best to turn off the AC switch to avoid engine load affecting acceleration. Keeping defogging wipes in the car for emergency wiping also works well.