Why Are Car Windows Fogging Up Inside When Parked

Why Are Car Windows Fogging Up Inside When Parked? [Explained]

You have probably seen car windows fogging up inside when parked. They are extremely annoyed as you need to clean them every single time. Do you know, what’s the reason behind this?

Car windows get foggy when there is moisture in the air. This also happens if there is not enough air circulation inside the car for a long time. The water vapour inside turns into liquid water, creating fog in the car window. 

Fogging up inside the car may happen anytime, but it’s common when the car is parked. This happens due to the condensation process, where water converts into its liquid state from vapour.

3 Reasons Why Car Windows Are Fogging Up When Parked: Check Now

There are several reasons why car windows are fogging up. Have a glance at the main reasons below.

1. Moisture Content

There can be moisture content from so many things inside a car. The humidity level can increase from the passenger’s breath as well. This elevates the moisture level inside a car.

The moisture content may increase even if you eat something hot inside the car. The steam from the food is humid and will fog up the window. 

The particles get cooled inside because of the heat difference and turn into water bubbles. When the bubbles wander inside the car, they get stuck in the window or windshield glass.

2. Weather

Car windows may fog up in both winter and summer. In winter, the car windows will start to fog up as soon as you get in the car. 

Car windows stay cold in winter, and when you get in the car, the warmth of your body and the car interior will create hot and wet air inside. This will condensate on the car window.

In summer, the same thing happens, but the fog will be some time on the outside of the window as the air outside will be more humid than the inside air. 

3. No Air Circulation

If there is no air circulation inside the car or the air is left inert for a long time, there will be water vapour or fog inside the car. It’s recommended to ensure a proper air circulation inside the car by either driving regularly or leaving the window open once or twice a week.

How To Fix Car Windows Fogging Up: Read Now

As you can’t drive with a foggy window, you should be aware of the solutions. Now you know the reasons, let’s find some ways to fix the fogging of the car window.

Use Window De-Mister

The window de-mister button of a car works great to fix the fog from the car window. Using this control, the car’s window glass will be heated to match the air temperature inside the car. This is to prevent condensation from happening.  

Remove The Humidity

Another solution to get the fog out of the window is by removing the humidity. This can be done in two ways. Either by opening the windows or by using the AC. To let the humid air from increasing, open the window to balance the inside and outside of the car.

When you turn on the A/C, it chills the air and gradually removes the humidity.

Park Car In Garage

Parking the car in the garage prevents fog in the morning. There is less moisture in the garage than outside. Parking the car in a shaded area can also be a good alternative.

Fix Any Dampness

It’s essential to keep the inside of the car neat and clean. Damp seats or carpets are the reason why condensation builds up inside a car. Make sure there is no damp upholstery inside. You may keep the car windows open when the sun is bright, and you’re not driving.


Why Is The Car Steaming Up When There Is No One In It?

Car windows may steam up even when you’re not in it. This is because there is moisture and dampness in the air. The water particles in the air get cooled down and become liquid.

The car windows usually get cold in the morning because of the temperature and cause the water to steam up even when no one is in the car. Sometimes the steam up may occur if there is any leak in the car.

Does Opening Car Windows Help Defog?

Opening car windows may help you defog if there is cold outside. This will work faster to defog the car window and the windshield. By opening the window, the moisture will be balanced.

By opening the window, the cold air will get inside the car and remove the humid air inside the car. That’s how the car windows will defog by removing the moisture.

Why Does The Car Fog When AC Is On?

When the AC is on, the glass will get cold. The air you are exhaling will have a lot of moisture. So, when this moisture-laden air meets the cold glass of the car window, there will be a layer of fog on the car window.

As a result, turning on the AC in cool conditions prevents fogging by equalizing the temperature between the glass and the surrounding air.

How Do You Defog Car Windows In Rain With AC?

When too much water is in the air, the windows fog up. The car window fogs up as it’s colder outside than inside. Sometimes, there will be fog on the window because the clothes are wet from the rain.

To defog the car windows in the rain, simply turn on the defrosters and turn up the heat. The AC will be automatically activated when the windshield defroster is turned on. 

What Is The Fastest Way To Defog Windshield?

If you need to drive the car immediately and there is fog on the windshield, there is a solution. You may apply a mix of water and rubbing alcohol to the fog. Mix ⅓ of water with ⅔ of rubbing alcohol. Spray the solution in the glass.

It will take a few seconds for the fog to disappear. Keep this solution ready if the fogging-up issue repeats.

Final Thoughts

Now you know about the reasons why car windows fogging up inside when parked. This is a common problem if there is a heat difference inside and outside of the car.

Try to maintain, and remove the humidity from the car and keep the interior fresh and clean, as dampness will create more fog inside a car.


Pennell, J. (2020, January 23). Defrost your windshield in seconds with this trick. TODAY. Retrieved February 28, 2023, from https://www.today.com/home/defrost-windshield-solution-t106477

Ugh! Why do my car windows keep fogging up?! (2014, November 6). USA Today. Retrieved February 28, 2023, from https://www.usatoday.com/story/money/cars/2014/11/06/cars-foggy-windows/18608683/

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