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If you’ve ever had a problem with your auto windows fogging, you know how dangerous this issue can be. Fogged windows can severely limit your outward visibility when driving, and this could cause an accident.

In this article, we’ll take a look at why windows fog. We’ll also offer a few tips and tricks you can use to clear and prevent fogged windows in different types of weather.

Why Do Car Windows Fog?

The air around us exists at varying temperatures, and it also contains varying amounts of moisture. When air reaches a certain temperature, the moisture it contains condenses and is released as dew. The temperature at which this condensation takes place is known as the dew point.

So what does this have to do with your auto windows fogging? Often times, there will be a difference in temperature between your car’s windows and the surrounding air. If your car’s windows are colder than the dew point of the air that surrounds them, the moisture in the air will condense on your vehicle’s glass. This will cause the windows to fog or mist up.

The extent to which this fogging takes place will depend on the amount of moisture in the air. The more moisture there is, the more the windows will fog. Fogging can take place on the inside of your car’s window or on the outside. Also, fogging can occur in either warm or cold weather.

If the day is warm and humid and you have the air conditioner running inside your car, this may cause your car’s windows to be colder than the dew point of the air outside. In a case like this, fogging may occur on the outside of your car’s windows.

On a chilly day when your car’s heater is on, the windows may be colder than the dew point of the air within the cabin. This may cause the glass on the inside of your car windows to become misty.

How Can I Clear Fogged Windows?

If it’s cold outside, you can clear condensation in a couple of ways:

  • Lower the windows. This will reduce the temperature of the air within the cabin so it more closely matches the temperature of the car’s glass windows. Keep in mind, though, that this may make the cabin uncomfortably chilly.

  • Turn on the defroster. The defroster in your car is designed to quickly heat up the glass on the windshield. This will reduce condensation.

In warmer weather, if condensation happens, it typically takes place on the outside of your car’s windows. You can get rid of it in the following ways:

  • Activate the windshield wipers. This will quickly remove condensation from the windshield.

  • Raise the temperature of the air within the car’s cabin. You can accomplish this by turning the air conditioner to a warmer setting or turning it off completely.

  • Turn off the car’s “recirculate” feature if it’s activated. This will allow air to enter the cabin that more closely matches the temperature of the air outside.

To prevent condensation from clouding your car’s glass, consider purchasing an anti-fog window treatment. Treatments are available that can reduce fogging on both exterior and interior glass.

Fogged windows can occur in all types of weather. Use the guidance discussed above to stop auto windows fogging.

Check out all the chemical products available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on how to keep your auto windows from fogging, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

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