You’re ready to roll on down the road. New adventures await! But no. The windshield is iced over or fogged up. Departure time is delayed—again. Have you ever wished you could quickly defrost/defog your motorhome’s or truck’s windshield? Me, too! Check out the quick solutions that I discovered. Then choose the trick that works best for you. You’ll hit the road in no time!
Cautions: No matter what, never attempt to drive a vehicle with a frosted/fogged-over windshield. It’s just not worth the risk of an accident. Also, never slosh hot water onto a freezing windshield. The temperature difference can cause the glass to break. Stay safe out there!
Defrost and clear the windshield faster
If several inches of snow have fallen onto the windshield, it’s best to remove most of the snow before applying any of these tips.
This Farmer’s Almanac idea is a classic. Cut a potato in half. The night before a frost, rub your windshield with the cut side of the potato. The sugars from the potato will prevent frost from forming. Use your windshield fluid and wiper to clear away the potato residue.
Air conditioner tip
Yep, you read that right. Here’s the air conditioning defrost/defog tip. (If you want to know the science behind this method, as well as a few additional tips, watch the video below.)
- Start the engine. Turn the heater on high/hot. Use the defroster setting.
- Activate your air conditioner.
- Be sure the air recirculation is turned off.
- Open windows a crack—even just a few seconds will help with the air exchange.
I was pleasantly surprised by how much quicker our windshield cleared when using this simple trick. The visor helps direct the heated air just where it needs to go!
- When exiting your vehicle for the night, flip the windshield visor down.
- In the morning, select the defrost setting.
- Turn the thermostat to a high heat temperature.
- Set the fan to its highest setting.
Note: If your vehicle features a remote start you can preset the defrost, temperature, and fan the night before. That way, you won’t need go outside into the cold until the windshield is clear.
Finally, here’s a simple defrost recipe made from items you may have inside your RV.
- 2/3 cup isopropyl (rubbing) alcohol
- 1/3 cup water
- Gently mix the two ingredients together.
- Pour the mixture into a spray bottle.
- Spray the alcohol/water mixture onto your frosted windshield.
Note: You can keep the spray bottle of liquid right inside your vehicle all winter long, because the freezing point of the alcohol is 138 degrees below zero.
How do you clear the fog/frost from your windshield? Share your tips and tricks in the comments below.
Intuitively, I’m thinking a bottle of the cheap $2/gallon antifreeze could be sprayed on the windshield… If it makes slush that’s fine, but if that froze into a sheet, then it’s really “sheety” antifreeze..
re: IPA & water mix for defrosting a windshield
IPA, as bought in the store, has more water in it than alcohol in the bottle. If you get very cold it will freeze up again before you can wipe it away. I learned the hard way in the mountains.
IPA? No, don’t spray a good pale ale on your windshield… drink it while you wait for the defroster to work.
We use a minimum of -20f (usually -50f) windshield washer solution in the vehicle on-board spray bottle. It works to remove frost and ice with the wiper blades activated. The Iso Alcohol also works but, as with any chemical, be careful with painted or clear coat surfaces.
Very interesting; thank you, Gail! We raise the front shades and let the warmth of the RV have a headstart on clearing the windshield ahead of starting the engine and applying the defroster. I’ll try the alcohol and water hint on the exterior to assist the heat from inside the RV. Thank you!
I buy a gallon of the commercial de-icer. Put it in a spray bottle and keep it by the back door. Pick it up on my way out the door. Spray the windshield and it’s ready before I put the bottle back and buckle up.
The easiest way would be to live in Key West. They are closing in on 8 years where the temperature has been about 50 degrees.
And the lowest temp ever recorded there is 41 degrees.
Speaking of Key West….Don’t forget the Fantasy Fest. It’s a complete riot!
But you will have to find RV parks about 19 miles away but make sure there is no full moon. Tides can be awful.
i agree, I live in Homestead where maybe 2-3 times in a year I might see a light frost, most years never.
Remember the gallons of hand sanitizer that you bought during the pandemic and didn’t use? I haven’t tried it (we live in South Carolina), but I would think that this would work as well as the isopropyl alchohol.
umm, likewise haven’t tried this. but know that most hand sanitizers also include some kind of lotion to offset the drying effects of alcohol. and some hand sanitizers don’t use any alcohol. Do I really want that smeared on my windshield?
In many vehicles turning on the defroster also activates the air conditioning compressor. This helps remove humidity from inside the vehicle.
That’s been normal for decades. Most, if not all, current cars don’t give you the option to not use the AC on defrost. You can usually hear the AC compressor engage when you select defrost.
Yep…I can’t remember the last vehicle I had that didn’t have that feature.
Agree, I a think the last one I had didn’t have AC.
I’ve never known the AC not to operate when defrost is activated.
That goes back to the 60’s
Hmm, when up north eons ago I thot we put heat on with defrost to clear windshield? Been in Florida so long I don’t even know where the defrost button is.