woman showing how to defog your windshield
Tips & Tricks

How to Defog Your Windshield: Here’s All You Need to Know

The slippery snow is not your only worry when driving a car during the peak of winter. The weather also causes your windshield to fog up and obstruct your visibility. If this happens, driving without taking care of this problem can threaten your safety. In this article, we will teach you how to defog your windshield and drive safely across town.

You must know that fog can form on the inside or outside of your windshield, depending on the weather you are trying to beat. If you are in the cold of winter, the fog will be on the inside, which is a result of the humidity from within the car compared to the cold weather outside. Conversely, the summer heat can also cause your windshield to fog when you turn on the AC.

Step-by-Step Process to Defog Your Windshield

To defog your windshield, you should not consider it sufficient to wipe it with your shirt sleeve or your palm. Any of these can scratch the glass, which may cause the sun to reflect into your face while driving. Instead, following the proven method will help you achieve the same purpose of visibility safely.

1. Turn On the Heater Fully

The first step is to turn on the heater entirely and let the hot air circulate within the car’s interior. Hot air can absorb a lot of moisture from the car interior, so it will help you suck the moisture causing the car to fog up. Once the car is filled with hot air, you can proceed to the next stage, which is also focused on reducing the moisture in the car.

2. Turn On the Air Conditioner

car aircon/ heater control

Next, you have to turn on the air conditioner. This may seem contradictory to the heater’s previously blaring functions, but you should not worry much. The air conditioning in your car is not just to cool the car during the summer. Its overall function is to regulate the temperature within the car.

So, when you turn on the air conditioner during the cold of winter, it absorbs more of the excess moisture in the air. The air conditioning coils will suck the moisture in the air as it passes over the ducts.

3. Turn Off the Air Recirculation Button

car air recirculating button

While waiting for the air conditioner to work its magic, you should remember to turn off the air recirculation feature. This climate control feature recirculates the air inside the cabin by closing the air ducts that lead outside. This option may be good if you’re driving behind a truck with a bad exhaust system or you’re driving through a smelly area but not when you want to clear a foggy windshield.

Since you want the air from outside to come into the cabin and help level the temperature differences, it will help to have this feature off. The recirculation feature is the button on the dashboard with a curved arrow inside a car symbol.

4. Crack the Windows Open

To hasten the process, you should open your car windows slightly. You may be reluctant to do this at first, but you should do it still. Allowing the cold air from outside to enter the car’s interior will help you close the gap between the temperature outside and inside the car. At this point, you should know that the temperature difference is the primary reason your windshield fogs up.

You should do this minimally and roll the windows up once the windshield is clear enough for safe driving.

How to Defog Your Windshield Automatically

Apart from the standard method for defogging your windshield, you can clear foggy windows automatically by using the defog feature in your car. Many cars come with this feature, which usually looks like a button with a box and three wavy vertical lines on it.

Once you press this button, your car goes through the defogging process automatically without you having to do things manually, like in the previous method. However, not every car has a defog option, which is where the standard method comes in.

When you press the defog button, your car’s heater and air conditioner work in tandem to remove the moisture from the air. It is then taken outside the car, where cold air is dragged into the cabin to balance the temperature. Gradually, you will notice the windshield and windows clearing up.

Tip for Keeping Your Windshield From Fogging

If you do not want to go through the hassle of defogging your car’s windshield every cold morning, it is better that you learn some ways to keep the fog away. We have highlighted some of the possible options below:

1. Use an Anti-Fog Spray

Another way to defog your windshield is to use a defogging spray. When you spray it on your windshield, it prevents condensation from forming and covers the windows with a translucent sheen. There are several brands of anti-fog sprays in the market, and you can walk into the nearest automobile store and ask for one.

To use an anti-fog spray, you have to start by cleaning the windshield and windows with a clean towel and a quality ammonia-free glass cleaner. Then, you should de-grease the surfaces with an alcohol-based surface cleaner. It is after this that you can use the anti-fog spray. 

Finally, leave it for a couple of minutes and buff the windshield and windows with a clean microfiber towel when it is dry.

2. Keep the Temperature Inside Your Car Close to the Temperature Outside

The primary cause of your car fogging up is the difference between the temperature inside and outside your vehicle. Thus, to keep your windshield from fogging, you have to ensure that the temperature inside the cabin is as close to that of the outside as much as comfort allows you. To do this, you can run the heater and air conditioner intermittently.

This method is more costly as running the air conditioner increases your car’s fuel consumption. If you want a more fuel-efficient method, you can crack your car windows open a bit to let in air from outside. This method will help you achieve the goal quickly and better fuel economy.

Finally, always keep your windows clean. Clean windows will prevent the windshield from holding onto grease and other particles that can cause the moisture level to rise.

Final Thoughts

Knowing how to defog your windshield is a skill you must know if you want to drive safely. If your car is one of the models with the automatic defog feature, you don’t have to worry about the strain or unpleasantness of the manual method. However, knowing how to defog your windshield may come in handy.