One of the reasons driving without a heater during the winter is dangerous is because a vehicle's window will frost up or fog and reduce your visibility.
If you need to drive in the winter, perhaps to get your vehicle to a shop to get your heater repaired, it'll be helpful to know how to defrost a windshield without a heater.
You can quickly defrost your car's windshield with de-icing sprays, homemade alcohol, water solutions, and scrapers. In addition, you can prevent frost and ice buildup by using a winter weather windshield cover on your vehicle.
Keep reading if you'd like to learn more about these methods, including step-by-step instructions and tips on properly defrosting your windshield.
Looking through a frosty windshield
Using An Ice Scraper
The most effective method to initially defrost a windshield without a heater is to use an ice-scraper.
One of the most effective ways to speed up the defrost process on your car's windshield is to scrape it.
Tips for scraping to defrost:
Scrape in a horizontal motion (left to right or vice versa) to reach the middle of your windshield
Scrape in up and down motions for the rest of the glass, moving from one side of the pane to the other
Apply firm and even pressure to the scraper by using both hands
When you've scraped off all the ice/frost, you can use a bristle brush or a broom to remove the loose ice.
The downside of this method is that the windshield will quickly frost and fog up again when you start driving.
Using an ice scraper on a frosted windshield
Home-Made Alcohol Solution
Did you know that household rubbing alcohol and water solutions can defrost your car windshield without heat?
Commercial de-icing products are water/alcohol solutions.
This is because alcohols have a much lower freezing point than water does.
Alcohol tends to freeze at more than -148 Fahrenheit, while water freezes at 32 Fahrenheit.
So, when you spray alcohol onto the ice on your windshield, you lower the freezing point of the ice, effectively making it melt.
To defrost your windshield this way, get an empty and clean spray bottle, some room temperature water, and some rubbing alcohol from your medicine cabinet.
Here's how to make and use a homemade alcohol solution for this method:
Use a ratio of 1 part water to 2 parts alcohol (i.e., ⅓ cup of water and ⅔ cup of alcohol)
Add this mixture to the spray bottle and secure the lid
Spray the windshield all over
Wait a few moments as the ice or frost begins to melt and trickle away
This method works better if you scrape the windshield free of as much ice as you can beforehand with an ice-scraper.
You can then apply the alcohol solution to your windshields outside and inside.
The alcohol solution should keep your windshield ice and fog-free long enough to get your vehicle to a mechanic's shop to fix your heater.
Spraying an alcohol spray on a frosted windshield
Homemade Alcohol Spray
In addition to using a homemade alcohol spray solution on your car's windshield after the ice and frost have taken hold, you can do so beforehand.
Consider spraying this solution of ⅓ room temperature water and ⅔ rubbing alcohol to your car's windshield the night before cold temperatures, snow, or frost are expected to settle in.
Doing so will create a base of alcohol solution that has a lower freezing point than the water (ice) that tries to form on the glass.
You should see a reduction of ice on your windshield the following day.
Store-Bought De-Icing Products
Another option that you can use for defrosting a windshield when your car is too cold to start, or you don't have a working defrost unit is using de-icing products.
Plenty of affordable products marketed as windshield de-icers and ice removal sprays are available in cold climates.
Some popular options that are very effective include the following:
Windshield Washer Fluid
The most practical way to defrost your windshield without a heater is to use cold weather washer fluid.
Winter windshield washer fluid is rated for various temperatures below freezing, usually down to -40 Fahrenheit or lower.
This is simply poured into your washer fluid reservoir in the engine bay in place of normal washer fluid.
For heavy snow or ice, you'll still need to scrape the windshield beforehand, but once clean, the windshield washer fluid should keep the outside of the windshield defrosted without a heater.
Although, the inside of the windshield will still likely fog up from your body heat and warm breath.
Filling up the windshield washer fluid reservoir with winter grade wiper fluid containing alcohol
Windshield Protection
Lastly, consider preventative measures to defrost your windshield if you don't have a heater.
While plenty of effective after-the-fact defrosting methods, you can protect the glass from forming ice and frost by using a windshield snow cover.
These products are designed and sold for all sizes and shapes of vehicles.
They're waterproof, windproof, designed to withstand extremely cold temperatures, and act as a barrier to keep winter weather out.
To use them, you simply have to tuck their corners into your car's shut windows or doors.
Or, if the windshield cover uses magnets, you can attach them to your car's metal body with magnetism.
Here are some great products to consider if you'd like to go this route:
Hint: Even a sheet of old cardboard tucked under the windshield wipers will work.
Conclusion
The best way to defrost a windshield without a heater is to use a combination of a winter-grade windshield washer fluid and an ice-scraper.
You may also need an alcohol spray to spray the windshield inside the vehicle. But, first, scrape as much frost off the windshield as you can.
While driving, use the washer fluid along with the wipers to keep the outside of the windshield defrosted, and use an alcohol spray to keep the inside of the windshield from fogging up.
FAQ
How To Defrost Windshield Fast
The quickest ways to defrost a windshield are to directly remove the ice/frost with a scraper and manpower or to use a store-bought de-icing spray product.
Note: some people wonder how to defrost windshields with water. Avoid this method if possible, as it could lead to more frost or damage/crack your windshield's glass.
How To Defrost Windshield While Driving
If you want to defrost your car's windshield while driving, you should use a hands-free method.
You could use the car's defrosting unit and wipers.
But if you don't have a defrost option, you can have windshield wiper fluid with a de-icing component already in the wiper fluid tank.