How to Stop Car Windows From Fogging Up in Winter

During the winter, not taking your car out and going on foot sometimes seems like the easy way out. After all, you have to shovel the snow, heat up your engine, and clean your windows every time you want to go for a drive. However, there’s no reason for you to have to do this every morning — the only trick is preparing your car for the winter.

By thinking ahead, you even can fog-proof your car windows, and cut your prep time significantly. If your knowledge on the subject is a bit foggy, here’s all you need to know about how and why fogging occurs — and how to get rid of it.

How to prevent car windows from fogging up in the winter.

Why Does Fogging Occur?

There are several factors at play here, but foggy windows typically come down to one thing — humidity. When humid air touches something cold, it condenses and creates moisture that forms the fog. The air can have different properties, such as moisture content and temperature.

The moisture content is the amount of moisture in the air, and it can be high or low. Additionally, the temperature is important when talking about moisture, as it determines whether the air would turn into frost or dew. To prevent fog from forming, there are also some activities that you should stay away from.

Activities That Can Cause the Inside of Your Car Windows to Fog Up

As you now know, the fog on the inside and the outside of your windows is caused by moisture. So, it only makes sense that you need to find ways to decrease the humidity and moisture in order to keep your windows clear.

There’s a number of everyday activities that can add up to create excess moisture. For example, hot liquids, multiple open containers with warm food, or even a talkative passenger will all pump humidity into your car. Also, if you have kids in the car and they’re fussing, moving around, and screaming —  they’ll release moisture at an accelerated rate.

Another factor that can make your windows fog up is an obvious one that often slips everyone’s mind — water. For example, you can generate excess moisture by not shaking the rain off your umbrella or clothes, or coming in with snow still on your boots.

You should try steering clear of these activities whenever possible to avoid generating moisture and fog. However, that’s not always a realistic expectation. So, here are the best ways to prevent your car windows from fogging in the winter.

How to Stop Interior Car Window Fog

Interior fogging occurs when the warm and humid air from the inside of your car touches the cold windows. When this happens, the moisture will condense and create the fog. Moreover, if the outside air is especially humid, or cool — the fog will keep building up even faster.

You’ll need to work on one or both of these factors to prevent interior window fog. So, you’ll either need to reduce the humidity levels, warm up the windows, or do both.

Turn the Windshield Defroster Mode On

Start by turning on your defroster to release some dry, warm air to the glass. As you know, the heat will prevent condensation from taking place. Also, the airflow will push the humid air out via the hidden vents in your car, made specifically for this purpose. You can also open your windows to hurry things along.

When you turn the windshield defroster on, your AC will probably turn on too. While some might think this is counterproductive and they turn it off, keep in mind that the cool air is essential in clearing the fog up. The AC will both dehumidify and cool your cabin, as well as reduce the amount of moisture inside your car.


Look at your owner’s manual to see how to control your car’s recirculation function, and turn it off when your windows get foggy. This way, the dry air will stay inside your car, and the humid air will be let out.

Keep the Climate Control System Healthy

Keeping your climate control system in good health goes a long way toward preventing foggy windows. Always make sure that your AC is working properly, your fan is in good shape, and the system isn’t making any strange noises. Additionally, check if there’s any debris blocking up your blower fan.

You also have to check your cabin air filter for any blocks. If there’s something preventing the air from flowing in your car, it’s probably what’s fogging up your windows. Simply clean your AC filter or replace it if it’s completely blocked. Once your climate control system is up and running, you can look forward to having clean windows all year long.


A dehumidifier can remove moisture from a home, greenhouse, and even your car. Additionally, it can prevent your car from constantly fogging up, and is a great long-term solution.

You can purchase a mini dehumidifier, as they’re typically spill-proof and won’t ruin the interior of your car. You could also go with a traditional product, such as DampRid that you can hang in any part of your car.

Shaving Cream

Believe it or not, shaving cream and commercial defoggers have a few ingredients in common. Thanks to this fact, you can use shaving cream to clean your windows and prevent them from fogging up.

All you have to do is apply shaving cream to the inside of your windshield, and gently wipe it off. Make sure to leave a small layer behind, as it will act as your DIY defogger. Moreover, this hack will help keep your windows fog-free for days, and you can reapply the shaving cream whenever you need to.

For full test and review of shaving cream as a defogger, see the video below:

Kitty Litter

Kitty litter can absorb quite a lot of moisture, and thus, can be quite useful in helping you combat fog inside your car. This is an incredibly cheap and easy solution, and you don’t even need to use a lot of litter to accomplish your goal.

To prevent your windows from fogging, simply fill a sock with kitty litter and let it sit in your car overnight. The litter will absorb the excess moisture instead of letting it sit and collect on the inside of your windshield.

However, keep in mind that you need to open your windows for a couple of seconds and let the cold air in. Because it’s dry, the cool air will help dehumidify the inside of your car.

Silica Gel

Silica gel can act as a dehumidifier, and help your windows stay fog-free all winter long. It’s cheap and easy to find, and all you have to do is place several packets inside your car. Silica gel is also reusable, so you can heat it up for a few hours for it to be effective again.

How to Prevent Exterior Window Fog

If the exterior of your window is fogging up, it’s because the humid air is touching the outside surface of your glass and letting the moisture condenses onto it. To clean your windows, you can turn your wipers on, turn your AC off, and let the glass heat up. It’s unlikely that condensation will form on a warm surface — so you can use the friction or heat to keep your windows clean.

To prevent the fog from clouding your windows in the first place, you could do one of two things. First, don’t leave your car in one spot for long periods of time. If your vehicle is constantly on the move, it’s less likely for the moisture to build up.

Additionally, avoid parking your car in a shady area, with little to no direct sunlight. The warmth from the sun will prevent condensation from forming on your car windows.

Anti-Fog Coating

Anti-fog coating can clean your windows and prevent any fog from forming in the future. One of my favorite products for the job is the Just Add Water Jaws Quick Spit Antifog Spray. It features a non-toxic, long-lasting formula and you can use it on both plastic and glass surfaces.

Simply apply the coating, and let it sit for a couple of minutes before rinsing the excess product off. You can let the product dry off by itself, or use a microfiber towel to wipe it off.

What Not to Do

There’s one thing you should absolutely avoid doing when you’re trying to de-fog your windows — recirculate. You have to ensure you’re breathing in fresh air from the outside, so the recirculate button should be off. Moreover, if you turn this mode on, you’ll only be recirculating your own breath. Thus, the moisture will never leave your cabin, and the fog will never lift.

Handle Your Foggy Windows Correctly

Foggy windows can be a nightmare — if you don’t know how to handle them correctly. Sometimes, the issue is that you think what you’re doing is right, but you’re actually making the situation much worse. However, now that you know what causes humidity, and what not to do — you’ll be able to rid yourself of fog forever. Hopefully, this article makes you feel prepared for the cold, humid winter months and helps you cut your car’s prep time significantly.




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