How To Defog Windshield

Defogging your windshield using a simple method and drive better with a clear vision

Car windshields and windows are bound to be foggy especially if you rarely open your windows.

The chances of this happening would be more especially in harsh conditions such as during the winter or summer.

When this happens the clarity through the windshield is interfered with and the driver is unable to see the driving path.

This would also make the car look less attractive as the fog makes the windows and windshield less appealing.

Defogging on windows is possible because of the principle of what cause the fogging either on the inside or the outside of the windshield.

You need to know that for this to be possible effectively, there should be a balance between the temperatures on the inside of the car as well as on the outside.

The following steps would ensure that your car windshield is defogged easily:

  1. Turn Heat On To Full Blast As Hot Air Holds More Moisture
  2. Turn On The AC
  3. Turn Off Air Recirculation
  4. Crack Open As Many Windows As Possible

When car windshields are affected by fogging, they pose a danger to whoever is in the car.

This might be worse when you are driving when it is raining heavily or through a storm, in this case you would not be able to control the fogging on the windshield as you can’t walk out of the car nor open your windows.

Things To Do To Prevent From Fogging Up Windshield

Most measures that car owners take are oriented to getting rid of the fog that has already occurred on the car windshield.

However, during extreme conditions like when you are driving during a heavy downpour or during the winter, the car windshield gets fogged up fast and this continues even after you wipe it off.

Getting out of the car to wipe the outside part of the windshield or even opening the car windows is not advisable as the weather outside is not that friendly.

This is why there are ways you can prevent your car windshield from getting fogged up.

  1. Making Use of the AC System: This method is one way you can keep your car windshield free from fogging and you would not be affected by the outside conditions. This works by setting the inside of the car temperature to match that of the outside. This means that during the winter, the conditions in your car will not be too humid which results to the formation of moisture which then condenses on the inside of car windshields.
  2. Windex: This is one generic cleaner that would be ideal to keep your car windshield from being fogged up. This is an effective method but if you are not careful when wiping it, you might leave ugly streaks on the glass. A good substitute of a generic cleaner that you can opt for is going for a dedicated glass cleaner such as Rain-X. This particular one is a specifically designed to prevent fogging on the car windshield while ensuring no significant residue is left behind. Unlike Windex, it does not damage car windshields by causing ugly and unattractive streaks on its surface.

Best And Fastest Way To Defog Your Windshield

Some cars have a simple defrosting button while some will need you to go through a number of settings to get this done.

The big question is what is the ideal combination of settings that will ensure that the defogging is done effectively.

1. Turn Heat On To Full Blast As Hot Air Holds More Moisture

This the first step to getting rid of fog that has already formed on the inside of the windshield.

Hot air holds more moisture and this condenses on the inside of the windshield and hence the fogging you have to deal with.

2. Turn On The AC

This is effective as it would help get rid of moisture that forms on the inside of the windshield.

Moisture needs to be gotten rid of from the air inside as it is what condenses and forms fog on the inside of windshields.

3. Turn Off Air Recirculation

This would ensure that the outside air, which is colder than that on the inside, gets in the car.

This air is dryer as it has less moisture. This would then cause the inside air which is more humid to move to the outside.

4. Crack Open As Many Windows As Possible

This would ensure that more humid air would move outside and leave space for lesser humid air from the outside to flow in.

For more details, you can watch this video:

Dealing With Foggy Windshield Inside And Outside Of Your Vehicle

Foggy car windows and windshield will be something you have to deal with as a car owner. This is whether it is more cold outside than in the car, or it is warmer outside than in your car.

You need to make sure that your windshield is free from fogging and hence clear enough when you are driving.

The last thing any driver want is to have their vision of the road they are driving on impaired by either too much fog or dirt particles.

Wipers might help but they would not be effective for cleaning the inner surface of the windshield.

The following is a detailed discussion about how to deal with a foggy windshield during different scenarios.

The steps here basically try to balance the temperature on the inside and outside so that both of them match.

1. If It’s Colder Outside Than Inside Your Car

During a cold weather, such as the winter, you may want to turn the heat up using the AC. This leads to fog forming on the windshield on the inside.

You can defog your windshield effectively and fast enough through:

  • Turn the heat to the point of maximum setting, simply because hotter air holds more moisture.
  • Turn the AC on, this pulls away the moisture from the air as it passes above the coils.
  • Switch off the recirculation button which will let in cooler and air with less moisture in the car.
  • Open your windows a little bit so that the humid air escapes and dryer air enters.
  • Otherwise, if your car has a defrosting button, you can hit it. This will blow warm air across the surface of the windshield on the inside and evaporate moisture that forms on its surface and impairs the vision through it.

2. If It’s Warmer Outside Than Inside Your Car

For this particular situation, the fogging would occur on the outer surface of the windshield.

The windshield wipers would not be able to clear this and at sometimes you are not in a position to walk out of the car wand wipe the surface of the windshield with a cloth.

Unlike when it was colder outside the car, here you will need to make the inside warmer:

  • Switch on the windshield wipers and let them work before you are able to achieve a balance in the inside and outside temperature.
  • Turn down the car AC so that it is at its lowest setting and let the temperature rise while it is comfortable to be in the car.
  • Switch off the car’s recirculation option which will ensure that the temperature and moisture levels between the inside and outside of the car is able to achieve a balanced level.

Q&A

There you go! Now you learned how to defog your windshield. Now what you will read the rest of the information is often asked by people who seek the main subject as you do. Keep reading!

How Do I Stop My Windows From Fogging When It Is Rains?

Fog on the window as well as the car windshield is because during a cold and wet weather, as it is when it rains, the car on the inside is highly humid.

This causes condensation on the glass surface, both laminated and tempered glass of the windshield and car windows, and this is the fogginess that causes impaired vision through either the windshields and the car windows.

One way to get rid of the fogginess is to turn your AC system on and set your car temperature to be as cold as it is out there.

This will ensure that the level of humidity in the cabin is controlled thus there is little condensation forming on the glass that impairs vision through them.

You can then use a clean and dry cloth to wipe off the fogginess that forms on the car windshield.

Turning on the AC will ensure that no more fog forms on the glasses.

Why Is My Windshield Fogging Up On The Inside?

During a cold weather, and maybe a damp weather, most car windshield will be fogged.

This is because on the inside of these cars is highly humid and this condenses on reaching the surface of the windshields.

This is because the windshield is cooled and causes condensation when the moisture reaches the surface of the windshield. This is what forms the fogginess as seen in some windshields.

How Do I Keep My Car Windows From Fogging Up In The Summer?

  1. Open the car windows and let the warm air from the outside into your car. This creates a sense of balance in the temperature of air both inside and outside your car.
  2. Another effective option would be using quality windshield wipers to clean the fog that forms on the outside of your car windshield. Wipers, the quality type, are designed to clean the car windshield on the outside effectively and hence leave them free from annoying fog that impairs vision through the car windshield.
  3. Getting a quality and top performing defrost would be another great solution to get rid of the frost that forms on either side of the car windshield. This would work effectively and you should be comfortable if you are not affected with the heat that utilizes in offering the end results.
  4. Other great solution ideas are setting the AC system to match almost the temperature on the outside or even drive with your windows down. The former would work well if you do not want to open your windows because of dust getting into your car and other factors. Having your windows down would be a great idea if you are in for a relaxing session.

Why Is My Windshield Fogging Up In The Summer?

During the summer, the outside temperatures are quite hot and it tends to be quite humid.

If you leave your car windows close for long this would lead to condensation on the car windshields because they have a lower temperature level.

How Do I Keep My Windshield From Fogging Up In The Winter?

The thing with the winter season, is that during the night a lot of fogging happens on the windshield and we wake up to a windshield that is not safe to drive in.

  1. One way to avoid this is leaving your car windows open for some time and let the cold air in. This gets rid of humidity in the car that would have otherwise led to the fogging of the car windshield. You should also take out bottles or open containers that might contain some moisture as they would increase the fogging extent on the car windshield. Defogging your car windshield during winter will need you to prevent the air inside your car from being too humid. This can be accomplished by first opening the car windows. It might get too cold, but you are probably dressed heavily for the cold weather.
  2. Secondly, turning on the AC system and setting it to a temperature almost similar to the outside would be effective in preventing the moisture from condensing on the inside of the windshield and causing the fogging. Preventive measures that would keep your car windshield from being fogged during the winter smearing the surface with shaving cream. This should be done on the inner surface and would prevent the condensation on the inside of windshield that makes the windshields less clear.
  3. Another simple and effective idea is to have a stocking or sock filled with kitty litter and leave it in the car overnight during cold nights. This would absorb the moisture that might have ended up forming on the windshield as fog.

Should I Use Hot Or Cold Water To Defog Windows?

Hot water would be effective in defogging the window as it has been seen to be highly effective in getting this done.

This would work for either sides of the windshield, provided you know what you are doing you will get the defogging completed in no time and the car windshield will be safe to use.

Does Shaving Cream Keep Windows From Fogging?

Yes, shaving cream is effecting in preventing your car window, as well as windshield from being affected by fogging.

Washing your car windows, windshields and even glasses with shaving foam is a simple yet effective way of keeping them free from fogging which makes it difficult for you to see through them.

What happens is that the shaving cream creates a protective film that covers the glass and keeps it from fogging.

Any soap would do the trick, but shaving cream is easier to apply. The protective film begins to wear away with time, but it will be effective for most parts of the day.

This solution would work if you realize that the car windshield is affected by the fogging and are not in a position to access defroster or any other solution.

Conclusion

All in all, the car windshield needs to be in good condition so that the driver’s as well as those inside have a clear vision through it.

Fogging is one process that occurs due to the temperature differences on the inside and outside of the car and impairs the vision of the driver as well as their passengers.

This would not only risk the lives of the occupants of the car, but would also be risky for other motorists using the same road as the driver.

There are many ways of getting rid of the fog on the car windshield, both on the inside and outside. Using the AC system and opening the car windows to let air circulate would do the trick.

Other measures are oriented towards keeping the windshield free from fogging as they prevent the fogging from occurring altogether.

One simple way is getting shaving cream and applying on the surface of the windshield, while a defroster would also be an effective solution.

Resources:

1. Digital Trends – https://www.digitaltrends.com/cars/how-to-defog-car-windows/
2. Allstate – https://www.allstate.com/blog/deal-foggy-windows/

Written by Yusuke Kohara

Hi there! My name is Yusuke. I write about automotive topics for Car Proper. I love cars and have a passion for writing helpful articles on tools, car accessories, and how-to to help my readers solve their problems. In my spare time, I'm either working out, reading the book, or spending time with my family. I also work for a digital consulting agency.

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