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How to Quickly Defog Your Car Windows

June 29, 2021

Driving with foggy windows can be a major safety hazard. Many people face the uncertainty of if they need to use heat or cold in this situation. If you struggle to defog your windows, we’ve compiled a few tips below that can help to clear things up.

Whether or not you need to use heat or cold to defog your windows depends on the temperature outside. On a cold day, any moisture in the air inside your car turns to condensation when it hits air next to the windows that is below a certain temperature. The condensation is what makes your car's windows appear foggy. On a hot, humid day, the opposite happens, when the muggy air outside your car reaches the dew point against your windshield after it's cooled by your AC system. In its most basic sense, the end goal is to match the temperature inside your car to the temperature outside.
 
When it's  colder outside your car than inside, the windows typically fog the exterior of the glass.
Here's what to do in that situation:

  • First, turn the heat to its maximum setting, because hot air can hold more moisture. In extremely cold temperatures, gradually increase the heat to avoid damage to your auto glass.
  • Next, turn the AC on, which will pull the moisture from the air as it passes over the cooling coils.
  • Finally, turn off the recirculation button so colder, dryer air is brought into the car.
  • If possible, crack your windows for a few minutes to help replace the humid interior air with dryer outside air.


When it’s  warmer outside your car than inside, the windows will typically fog up on the exterior of your auto glass.

Follow these steps in this situation:

  • First thing: Use your windshield wipers. This will help get rid of the condensation until you've balanced out the temperature.
  • Warm up your car: Turn down the AC to the lowest (least-cool) setting to increase the temperature without it becoming too uncomfortable. If this doesn't work, turn the AC off completely.
  • Leave air recirculation off: As stated above, it's a good idea to turn off your car's recirculation feature to battle foggy windows so the temperature and moisture levels in your car begin to equalize with those outside.


Every once in a while, extreme temperature differences can cause cracked or shattered windshields. When this happens, there is no need to panic. The auto glass experts of Abra are here to help! Whether you need a simple repair or a full windshield replacement, we can handle any of your auto glass needs. Be sure to take advantage of our FREE Mobile Windshield Replacement service!

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