5 Of The Quickest Ways To Defog Your Car's Windshield

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There are few situations more frustrating for a driver than driving a car with fog all over the windshield. It gets even more challenging when the fog starts building up immediately after it's been wiped off. This usually happens during winter and rainy reasons — your windshield fogs up due to condensation, which occurs when humid air inside your cabin comes in contact with a cold surface of a windshield.

And aside from the annoyance, driving a car with a foggy windshield is also extremely dangerous. According to a report by the U.S. Federal Highway Administration, every year over 38,000 accidents occur because of low visibility and fog. A blurry windshield can lower your visibility, and make it difficult to see what's on the road, especially pedestrians and smaller vehicles. Therefore, knowing the right techniques to defog car windshield is vital. Understanding the correct methods to protect the car's windshield makes things much easier for the driver for a clear view and a safe journey.

If upgrading your car's windshield to avoid fog build up isn't an option for you, we have compiled a list of five quick ways that can help defog your car windshield condensation effectively.

Your car is equipped with features to defog your windshield easily. There should be a button to blow air on it located in the AC controls, and can be identified by its logo — a rectangle with wavy lines rising upward. When you press this button, the air is mechanically directed toward the windshield via the front air vents located on the dashboard. However, turning on the windshield air flow might not help in effectively reducing the fog. You may also need to balance the inside and outside temperature difference.

Fog builds up when the moisture in the air condenses on the glass, and that's usually a result of the cabin temperature being significantly different from the outside air. In such a scenario, turning the temperature of the AC to the maximum will act as a dehumidifier to remove moisture, and pressing the button will direct that at the windscreen. This will dry the air inside your car and cause the moisture to evaporate quickly, while also ensuring that the inside and outside temperature difference in minimum.

Fortunately, modern cars have the feature where when you press the defogger button, the AC is engaged automatically with the optimal fan speed to dry the air. You can apply the same technique and use the rear defogger feature to reduce the fog on the rear windshield.

Older and lower-trim models may not have a defogger that automatically engages the air conditioning, but you simply blasting the AC at full speed can also reduce fog. Switching it on when it is cold outside might seem odd, but it can be effective/ AC isn't just for cooling, after all.

Turning on the AC can help dry the air inside the cabin and dehumidify it. You don't need to set a low temperature. Even when the AC is set to blow warm air, it gets rid of humidity and the warm air evaporates any remaining moisture from the air, eliminating fog settlement on the windshield.

If the fog is taking a long time to disappear or doesn't disappear at all, there might be a problem with your AC. Another very common sign of AC trouble is a strange smell coming from the vents as soon as it is switched on, which happens when moisture gets trapped inside the air conditioning system. In such a situation, you may need to get your AC repaired, and once that is done, it will defog the car windshield much faster.

Just like the people often misunderstand the AC button to only blow out cool air, there are some misconceptions about the recirculation button. The main idea of putting a recirculation button in a car with an AC system is to allow the car to recirculate the already available air inside the cabin and avoid drawing fresh air from the outside, which in turn also accelerates the cooling process.

However, it shouldn't be turned on when you are stuck in traffic or parked in a closed space, as it will suck the outside exhaust gases and trapped air inside the cabin. It is also essential that you do not use the recirculation button if you want to get rid of a foggy windshield.

Fresh air from outside needs to enter the car to defog the car windshield, which will not happen if you turn on the recirculation button. You might need to manually turn off the recirculation button because in many cars, when you blast the AC at full speed, it automatically turns on the recirculation button. Let the fresh air enter the car, quickly dry the trapped air inside by mixing with it and prevent the build up of fog in the windshield.

Most of the above solutions stress getting fresh air inside the car's cabin to defog car windshield condensation, and what better way to give outside fresh air a big opening to enter the cabin than rolling down all the windows? This is not only effective, but one of the quickest ways you can get rid of the moisture in the trapped air and defog the windshield.

Rolling down the windows for a while will help equalize the outside and inside temperature, thereby reducing the condensation that forms the fog. The inside air can become humid because of your breath, wet clothes, liquid food items, and more. Simply rolling down the window introduces dry air from outside, making it difficult for fog to form on the windshield. And you don't need to keep the windows down all the time to prevent fog formation.

Once enough fresh air has entered the cabin and the fog has disappeared, you can roll up the windows. A pro tip, which my dad taught me to prevent fog, is to keep the window slightly opened (an inch or so). This trick works great, but it is effective during rainy season or mild weathers, not when it is freezing cold.

Another way of keeping fog build up at bay is to use a compact dehumidifier to absorb the moisture in the air and prevent fog formation on the windshield. Apart from sucking up moisture, a dehumidifier can also help get rid of mushy smell or growth of moisture-prone bacteria inside the car. There are a lot of dehumidifier options available online that actually work. You can opt for either a portable dehumidifier or disposables ones. A portable one will connect to your car's USB charging port and actively pull out moisture from the air and collect in a tank.

I have also found the disposable car dehumidifiers work as well as a portable one. While the powered dehumidifiers work faster and much better compared to the disposable ones, the disposable ones are cheap and don't require power to function. They come in a bag, which is filled with moisture absorbing materials such as silica gel, calcium chloride, or activated charcoal. They trap moisture inside them and keep the air dry. However, you need to change them as soon as you see their effectiveness go down, or change in the bag color.