How to Defog Car Windows in Winter?

[VanRafael]

Methods to defog car windows in winter include: opening windows for air convection, using the air conditioning system to defog, applying professional defogging agents, and using dishwashing liquid to prevent fogging. The most commonly used method is opening windows for air convection. If the fog inside the car is not heavy, you can slightly open the windows on both sides to create air convection between the inside and outside of the car, which reduces the temperature difference and gradually dissipates the fog. Additionally, specialized defogging agents can be used. Spray the specially formulated glass cleaning and defogging agent onto the car windows and wipe it clean. While removing dirt from the glass, it also forms a thin protective film that effectively prevents moisture from condensing on the glass and forming fog. Generally, one application can last for a day of continuous fog prevention.

[Lukas]

Foggy windows while driving in winter is a common issue I often encounter, especially during commutes. My first response is to activate the car's defogger function—pressing the button with the airflow symbol pointing at the windshield, cranking the fan to maximum, and letting cold or warm air disperse the fog. The air conditioning's dehumidification mode works wonders, quickly absorbing interior moisture. If it's cold outside, I wait a few seconds for the engine to warm up before defogging, then adjust the temperature to around 20°C for comfort. Preventatively, I wipe the inside of windows with a dry towel before driving to minimize condensation buildup; turning on recirculation speeds up defogging, switching back to fresh air mode afterward to prevent odors. Safety is paramount—if fogging is severe, I pull over to address it rather than risking driving. Regularly cleaning the AC filter also helps reduce fogging frequency.

[McRemington]

As a novice driver, finding the windshield fogged up in winter can be panic-inducing. The method I learned is to directly press the car's quick defogging button (often labeled 'FRONT DEFOG' or 'FRONT DEFROST') and set the fan to high speed blowing towards the windows. The A/C button must be turned on because cooling dehumidifies quickly—even though the air might feel cold, endure it for a few seconds until the fog clears. Remember to check the air recirculation mode: use recirculation for quick dehumidification when fog appears, then switch to fresh air mode for ventilation after the fog dissipates. If there's no button, turning on the heater and directing airflow to the windshield also works, but it’s slower. Novices can keep a cloth in the car for emergency wiping. To prevent fogging, avoid leaving damp clothes or wet items in the car. After defogging, maintain a low fan speed to keep the interior warm and ensure safe driving without distractions.

[McNolan]

I use a simple method to defog: After starting the car, immediately turn on the heater and direct it at the windshield with the fan at maximum speed. The fog begins to dissipate within seconds. If the fog is heavy, quickly turning on the A/C mode can assist in dehumidification more effectively. Keeping a dry cloth handy in the car for wiping helps a lot, especially when manually clearing fog before driving. To prevent fogging, I occasionally spray a commercial anti-fog agent on the windows to form a long-lasting anti-fog film. Remember not to blow hot air on a very wet windshield as it may cause fogging again; first use cold air or dehumidification mode, then switch to warm air to maintain temperature. Maintaining good habits like regularly cleaning the inside and outside of the windows reduces problems.