How to Defog a Car Windshield in Seconds

By Max. D Gray. Updated: August 20, 2019
How to Defog a Car Windshield in Seconds

There are some advantages to living in a cold climate, but keeping your car in top condition often isn't one of them. Glass can crack, liquids can freeze and the conditions of the road can be very dangerous. One less hazardous, but very annoying winter car problem, is that the windshield can fog up just when you need to drive

If you need to defog your windshield quickly, keep reading here at oneHOWTO and we'll show you how to defog your car windshield in seconds.

You may also be interested in: How to Clean Your Car Windshield Better

Car windows fog up when parked

On cold and rainy days it is very common for car foggy windows to appear on your car windows or windshield. This can result in a loss of visibility on the road and put you and everyone else in the car at risk.

The primary cause of car windows fogging on inside is the temperature and humidity difference between the inside and outside of the vehicle. Because the weather outside is colder than the air inside of the car, the relative humidity point is lowered, and the warm(er) air inside condenses on the window (as it is cooled by the outside air). Car foggy windows simply refers to moisture which has become condensation on the car window.

For more, we recommend taking a look at our article where we discuss how to avoid foggy car windows.

Haze on windshield

Your car windshield can fog up overnight if you previously had the heater on while driving, specifically because the warm air remaining in the car turns into condensation and fogs up the windshield and windows as it cools.

This type of fog is usually even harder to displace as it might freeze in colder temperatures. However, it can also happen while you are driving the car as, especially when you have the heating on high. Defogging it can sometimes be tricky, especially if you don’t have a defog button in car.

Do your car windows fog up easily? keep reading to find out how to defog your car windshield!

How to Defog a Car Windshield in Seconds - Haze on windshield

Defog car windows without ac

To defog your car windows we suggest letting air circulate freely inside your vehicle. This is an effective way to defog your windshield, but it is not necessarily the quickest. We recommend lowering your car windows and in a few minutes you’ll notice your car windows clear up.

Defog car windows in summer

If this first tip doesn’t work and your windows are having trouble defogging, apply the hot, dry air from the car heating system directly onto your windscreen. Select the icon button that represents a window and three arrows pointing towards it. If your car doesn’t have this defogging button, turn on your heating and it should gradually defog the windshield and car window.

It will take longer to defog the windshield if the heat is not positioned directly toward the window.

For more, read how to clean your car windshield better.

How to Defog a Car Windshield in Seconds - Defog car windows in summer

Defog car windows during rain

You can also defog your car windows with your AC, especially in the case of rain. This method, however, does take some time, as cold air is not able to hold as much moisture as warm air.

For more information, take a look at our article on how to defog a windshield with AC.

How to Defog a Car Windshield in Seconds - Defog car windows during rain

DIY anti fog winshield

Rubbing the windshield glass with your hands can help remove condensation but only momentarily, so it's not the best way to defog your car.

We recommend soaking your windscreen with a mixture of soap and water before starting to circulate. After passing a dry cloth over the windshield, remove the soapy solution well. This DIY trick will help avoid your car from fogging up too quickly.

How to Defog a Car Windshield in Seconds - DIY anti fog winshield

Defog car windows spray

Alcohol is another great way in which you can defog your car window. Make this DIY care defogging solution by:

  1. Mixing 1 part water to 2 parts ethanol or rubbing alcohol.
  2. Shake together.
  3. Place this solution into a spray bottle and spray it on to the windshield and/or car windows.

This is definitely the quickest way to defog your car windshield and, because alcohol is so low in temperature, it will not freeze if you leave it in the car like some other products might.

How to Defog a Car Windshield in Seconds - Defog car windows spray

How to defog car window

Finally, remember that your engine should be at a temperature of about 90 degrees for your windscreen to defog properly and quickly. If your car has air conditioning, defogging the windscreen of the vehicle will be much easier.

In addition, in order to avoiding window fogging, we recommend always keeping your windows clean with a car window cleaner. Additionally, you can buy some anti-fog products at your local motor store which are made specifically to prevent window fogging.

If you want to read similar articles to How to Defog a Car Windshield in Seconds, we recommend you visit our Car Maintenance and Repair category.

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1 comment
I read a tip for keeping your windshield from fogging up. Fill a sock with kitty litter and keep it in the car The litter soaks up the moisture that condenses on your windshield. I am trying it out tonight to see how well it works.
OneHowTo Editor
Hi Greg,

Thank you so much for sharing. Kitty litter does work as a dehumidifier, but we have not specifically heard about it being used for this reason. Let us know how you get on so we can know if it works!
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