How to Defog Your Windows in Any Weather

Anyone who’s dealt with their car’s windshield fogging up knows it can be both frustrating and dangerous. Window fog is due to condensation, so understanding the cause of that condensation will go a long way toward quickly eliminating your foggy windows.

How to Defog Your Windows When It’s Cold

Warm air holds more water vapor than cold air, and the warm air inside your car absorbs moisture from your breath, wet shoes, and damp clothing. In cold weather, the outside air cools the glass windows, creating the perfect conditions for the moist air inside your car to condense and fog your windows.

Although it may seem like a quick solution, don’t wipe away the condensation on your windows with a cloth or your hand. Without adjusting the environment that is causing the fog, you’ll see more condensation return.

In winter, the key to defogging a window—and keeping it defogged—is warm, dry air. Turn on your car’s heater to get things warmed up, and turn on your air-conditioning system to keep the air you’re introducing nice and dry. That’s right: Even in winter, you should use your air conditioner to keep your windows clear. Air conditioning (AC) doesn’t just cool your car; it’s an invaluable tool to rapidly de-fog your windows in the winter, helping you drive safely.

Getting into a cold car and immediately turning the blower fan on full blast may not be the best—or quickest—option to dealing with a fogged window. Use your fan’s medium speed to allow the air more time to warm and dry before it’s directed at the windshield. Make sure you have set your vents to the defrost setting, too, as this will preferentially direct air at the windshield.

If your car doesn’t have AC, make sure you are allowing air from the outside into your car. Set your interior vents to fresh air instead of recirculate. Cracking a window is also helpful, which allows the wet air to escape as it is replaced by dry air.

How to Defog Your Windows When It’s Hot

While less problematic than a foggy window in cold temperatures, summer’s hot and humid outdoor conditions may also fog up your windows. Unlike in the winter, the fogging will occur on the outside of the glass, where the season’s warm moist air condenses on AC-chilled windows. You can use your windshield wipers to clear fog on the outside of the windshield as an immediate, temporary measure to restore visibility. However, the key to preventing the fog is to allow the windows to remain warm. Redirect your car’s vents away from the glass, don’t use the defrost setting, and consider turning up the interior temperature slightly.

Know the Difference: Defogging vs Defrosting

Frost is moisture frozen on your car’s window glass. It can be either from frozen fog and mist on the inside of your windows, or it can be ice and snow on the outside. To clear your windows from frost, you will either have to manually scrape the frost off or melt it and then dry the water.

Many cars have an electrically heated rear window which will warm the glass, melting ice and drying off the fog. Once the glass is warm, it is much less likely to fog up again. If the outside of your windshield is covered with snow and ice, you can speed up the process by clearing the windshield with a snow brush and scraper. This will make it easier for the system to melt and clear what remains.

Be patient. Start your car five to ten minutes before you need to drive, so it has time to melt the frost. Once the engine is warmed up, warm air will melt the ice and dry the residual fog and moisture, restoring visibility with little effort on your part.

Pro Tip: Keep Your Windshield Clean

You can take a few steps to reduce fogging and make it easier to defog a window if it appears. First, keep your windows clean—especially the inside surfaces. Even a slight haze from dirt can affect visibility in certain conditions. When you combine that dirt with fog, things can get dangerous.

Plus, a dirty window is more likely to fog up than a clean window. The tiny dirt particles are ideal areas for water to begin to condense, causing fog to occur more quickly and more often than it would on a very clean window.

There are also specialized anti-fog treatments you can use on your windows. In combination with a clean window, these materials work well to stop fogging by reducing your windows’ surface tension and dispersing the fog’s micro water droplets into a thin water film that is much more transparent. Most products come in a liquid form, which you apply to a clean, dry window and polish to an invisible film.

The Bottom Line

Foggy windows don’t have to be a problem or a hazard. If you understand the weather conditions causing the fog and know how to properly adjust your car’s ventilation controls, you can eliminate and prevent a fogged window quickly and easily. Take the time to understand your car’s different fan speeds and heat settings, and figure out where to set and direct your vents to get the best and quickest de-fogging performance from your car. Keep your windows clean and, in extreme climates, consider an anti-fog treatment to reduce fogging before it starts.

How to Remove Frost from Car Windows

A telltale sign that winter has arrived is when your car windows are completely frosted over. Frost occurs on windows in the same way as dew does ? when the temperature of the glass becomes lower than the surrounding air, condensation forms on the window. If the temperature is at or below freezing levels when this process occurs, frost forms instead of dew.

Frost can be a thin or thick layer, and it can be of dense or light consistency. Frosty windows aren’t pleasant to deal with and can be fixed if you have the spare time to deal with them properly.

Scraping your windows is time consuming, and in several southern states where frost seldom occurs, you may not have an ice scraper handy to deal with the frost. However, there are a few ways to remove frost in a quick and easy way so as to avoid damaging your vehicle.

Method 1 of 5: Melt the frost with warm water

Materials Needed

Step 1: Collect warm water in a bucket. Heat water until it’s lukewarm.

You can use either a kettle to warm up water or use warm tap water directly.

The amount of lukewarm water you need depends on how many windows you need to defrost.

Tip: The temperature of the water needs to be comfortably warm on your skin but not hot.

Warning: Using very hot or boiling water can cause your windows to crack or shatter. The extreme temperature difference between the cold glass and the hot water will cause rapid, uneven expansion that can crack your window.

Step 2: Pour warm water over your windows. Pour water over the whole surface that you need to clear.

You’ll notice that the white frost changes to a translucent, slushy mixture or it may even completely melt away.

Step 3: Remove the slush from your window. Use a gloved hand or a scraper to remove the slush from your window.

If there is still an icy coating on your window, it will be easy to remove with the scraper. If there are spots that you have missed, pour more water on them to remove them.

This method is excellent for temperatures at or just below the freezing point.

• Note: If the temperatures are much cooler than freezing point, say 15 F or below, there is a high probability that the warm water you pour on your car will turn to ice in other areas as it runs off your car’s surface. This has potential to leave your windows clear but frozen shut, your doors frozen closed, and areas like your trunk and your hood difficult or impossible to open.

Method 2 of 5: Use a de-icing fluid

De-icers are popular products to use in colder climates. They are often used for small problems like frozen door lock cylinders and frozen window frames, and are now increasingly being used to clear frosty windows.

De-icing fluid is made mainly of an alcohol such as ethylene glycol and isopropyl alcohol, though isopropyl alcohol is more common because it is less toxic. The de-icing fluid has a much lower freezing point than water, making it perfect for melting frost from windows.

You can purchase de-icing fluid at hardware stores or you can make your own by mixing three parts vinegar to one part water in a spray bottle. Alternatively, you can also mix a cup of rubbing alcohol with three drops of dish soap in a spray bottle to make a solution.

Step 1: Spray de-icer on the window. Spray a liberal coating of your de-icing fluid on the window that is frosted up.

Let it ‘soak’ or melt into the frost for about a minute.

Step 2: Remove the slush from the window. Use your wipers or a gloved hand to remove the melting frost from your window.

If there are bits remaining, either spray with your washer fluid and wipe off with your wiper blades or apply de-icer to those spots again.

In really cold weather such as 0 F or below, you may still need to use your scraper to remove some of the frost, though the de-icer spray will make it much easier and less time-consuming.

Method 3 of 5: Scrape off the frost

When your credit card or membership card expires, keep it in your wallet for emergencies or situations where you may not have a window scraper handy. You can use an old credit card as a window scraper, clearing your windows so you can drive safely. However, keep in mind that it will take a while to effectively clear the window with such a small contact surface.

Step 1: Use an old credit card. Select a card that you seldom use. Don’t use your most actively used cards because there is a very real chance that you may damage the credit card.

Step 2: Put the credit card against the glass. Hold your credit card lengthwise, keeping the short end against the glass.

Use your thumb to slightly bend the card lengthwise to provide extra rigidity. Hold the card at an angle of around 20 degrees where you can apply pressure without the card buckling.

Step 3: Scrape away the frost. Scrape forward with the card, digging into the frost on your windows.

Be careful that the card doesn’t flex too much or it could snap in the cold temperature. Continue scraping until you have a usable viewing area.

Method 4 of 5: Use the windshield defroster

When the temperatures outside are cold, your car’s engine takes several minutes before it produces heat. When there are no other choices but to wait for assistance in conjunction with the above methods, use the defroster in your car.

Step 1: Start your engine. Your vehicle will not produce sufficient heat to clear the windows unless the engine is running.

Step 2: Change the heater settings to defrost. Turn the heater settings to defrost.

This sets the mode door on the heater box to direct air out the vents by the windshield, blowing directly on the inside of the windshield.

Step 3: Turn on the rear defrost grid. It is the button that has similar vertical wavy lines in a square box.

This is an electrical grid that will heat up in the same fashion as a light bulb does. The heat generated from the electrical grid will melt through the frost on the rear window of your car.

Step 4: Scrape the windows. As an additional assistance to the windshield defroster, scrape the windows with a scraper or a credit card as indicated in the previous methods.

As the windshield warms up, the scraping will get much easier and will take much less time.

Method 5 of 5: Prevent frost formation on your windows

Step 1: Use a de-icer spray. Many de-icer sprays such as CamCo Ice Cutter Spray do more than just removing frost from your windows. Using the de-icer to prevent frost from forming on your window again. Just mist the de-icer over your windows when you park your car and frost will not form or adhere to the glass well, making it much easier to remove.

Step 2: Cover your windows. Covering your windows when you park will prevent the majority of frost from forming on your windows. Use a blanket, towel, sheet, or piece of cardboard to cover your windows when you park.

• Note: If the conditions are wet, this method is not advised as the material can very easily freeze to the glass, making it even more difficult to clear your windows instead of easier.

Another option is a windshield snow cover like this one from Apex Automotive that covers your window and is easy to remove, even in wet conditions.

Unfortunately, most people cannot avoid having to leave their vehicles parked outside at one time or another. If you are aware that the conditions outside ? low temperatures, high humidity, approaching nightfall ? are conducive to frost forming, you can employ a method to prevent frost from forming on your windows.

This article originally appeared on YourMechanic.com as How to Remove Frost from Car Windows.

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Clear Frost From Car Windows

Introduction: Clear Frost From Car Windows

One of the less fun things about winter is having to drive in it. Going out in the morning to find that you can’t see into (or out of) your car windows is even less fun. It’s just added to the time it’s going to take you to get anywhere and it’s going to make you either stand next to your car and scrape the windows or sit inside with your car and defroster running until you can see through them (blowing COLD air around until it starts to warm up).

Frost is pretty, but it’s cold and not fun to remove. Here’s a very quick, cheap, and easy way to get rid of it. (I cleared my windshield this morning in about 15 seconds.) It works best when the outside temperature is above 25°F. (-4°C.)

NOTE: Please keep in mind that this is a method of removing frost, not snow or ice, although it may work if it’s not too cold and the ice or snow are thin enough.

Step 1: Tools Needed:

Empty milk jug (gallon or half gallon) One less in the landfill.

Squeegee (long-handled is better — available from auto parts stores or departments — or even Harbor Freight Tools)

Water — inside room-temperature (60-70°F , 15-21°C) works best, but you can use cold water right from the faucet. You just may need more of it.

Step 2: Getting Rid of the Frost

Probably the best way to do this is to fill your jug the night before and leave it by the door you normally go out. That way you can grab it as you leave.

DO NOT USE HOT WATER. You can crack your windshield.

When you get to your car and find all that nasty frost on the windows, get in your car, start it up, and turn your windshield wipers on high (fast). Unless the frost is already melting, this won’t do much good — maybe scrape a little off the surface, but your wipers will quickly wipe away the water you’re about to pour on. Get back out of the car (or stand between the door and the opening) with both car and wipers running.

DO NOT LOCK YOUR DOORS — this will tend to make you very late for whatever you were planning to do.

Stand to the side (to keep your wipers from throwing freezing water on you) and pour the water over your windshield. The water will be warm enough to quickly melt the frost and warm up the windshield to prevent ice from forming before the wipers can remove it. If some ice does form, simply pour more water on. The third picture was taken about 15 seconds after the first one.

If side or rear windows are also frosty, you can use some water and the optional squeegee. Pour it on and quickly squeegee it off before it freezes. It also works on rear-view mirrors, but not as well as they are often recessed and the squeegee can’t get to them very well. When enough frost is gone to see clearly, put the top on your water jug tightly and put it on the floor of your back seat or in the trunk and you’re ready to leave. (Remember to take it back in the house when you get home.)

Step 3: Another Word of Warning:

If your windshield has stone chips this method may start a crack. If you already have cracks, this method can
cause the glass to crack further — make an existing crack run very quickly. It doesn’t always happen, but you are applying stresses to your window by suddenly changing its temperature.

I will not be responsible for cracked or broken windows — I’ve tried to warn you.

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