What to Do When the Car Fogs Up Due to Cold Garage and Hot Outside?

[LaAlaina]

Here are some solutions for defogging: 1. Air Conditioning Defogging: This is the simplest method. Just turn on the front window defogging mode, set the fan speed to maximum, turn on the A/C switch, and adjust the temperature to the lowest setting. The fog on the glass will disappear shortly. Additionally, some models have electric heating for the rear windshield and side mirrors, which can eliminate fog in about a minute when activated. Many vehicles now also feature a one-touch defogging function, which is both convenient and quick to use when fogging occurs. 2. Air Convection: This method is suitable for very few situations. Opening the windows increases air convection, reduces the temperature difference between the inside and outside of the car, and weakens the conditions for fog formation. While this method seems economical, it is rarely practical, especially if it's raining outside, making it impossible to keep the windows open. Moreover, the incoming airflow is quite limited. 3. Defogging Spray: Simply spray it evenly on the glass surface and wipe it clean with a dry towel. The principle involves using surfactants to leave a protective film on the glass surface, altering the surface tension of water molecules so that fog droplets coalesce into larger droplets, thereby not obstructing the view. This can also be applied to other car windows, especially the side mirrors. 4. Homemade Defogging Spray with Dish Soap: Mix dish soap and water in a 1:6 ratio, store it in a bottle, and spray and wipe before heading out. The effect is comparable to commercial defogging sprays, though the durability is slightly inferior.

[BrandonDella]

Here's how I usually deal with the issue of foggy windows caused by the temperature difference between a cold garage and warm outside air, having driven for over a decade and seen it all. At the first sign of window fogging, I first turn on the windshield wipers to tackle external condensation—it works instantly. For interior fogging, I turn on the AC, press the front defroster button, and make sure to activate the AC and recirculation mode. A blast of cold air clears the fog in seconds. In cold weather, using the heater also works, though the fog may worsen initially before clearing up in a minute or two. Cracking the windows slightly can quickly balance the temperature difference and is more fuel-efficient than relying solely on the AC. I always keep a clean chamois cloth in the car; for light fogging, a quick wipe does the trick. Applying a bit of soapy water to the interior glass before heading out works surprisingly well—it's cheap and leaves no residue. These methods have stood the test of time and, most importantly, ensure safe travels without delays.