By Gail Marsh
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.
Potato tip
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.
Visor trick
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 to go outside into the cold until the windshield is clear.
Magic recipe
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.
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RVDT2838
Great tips Gail! Unfortunately, there is no fast way that I have found to defrost a Class A windshield other than lots of patience.
Gail, most newer trucks use the a/c when in the defrost mode. Even Fords F53 chassis. Fyi
Thanks for your input, Ray. I didn’t know that!
Safe and happy travels to you!
The potato trick sounds awfully messy! We lay a heavy towel or small lightweight throw rug over the windshield the night before.
The interior of the windshield fogging is due to humidity in the vehicle. A cup of rice helps lower the moisture in the air and quickens the wait time.
Leaving one of the side windows open a crack helps. Humidity accumulates when the temp inside is higher than outside. Leaving the window open allows the warm humid air to escape.
I have the rain guards n my pickup. I can leave the window open a1/4 inch.
Thank you for the suggestions and noting the video, Gail. We rarely encounter this and typically only use the defroster and, once they become unfrozen, the windshield wipers. Rarely, I have the foresight to put winter-formula windshieldwasher fluid into the reservoir. If I did manage that, then I spray it onto the windshield as well. Have a great day and safe travels!
I don’t put the winter deicer in the reservoir. I put it in a spray bottle and just spray it on the windshield.
No sense wasting the expensive stuff every time you hit the washers.
A gallon will last 2 years.
The A/C trick is only useful for defogging the inside of the windshield. Most vehicles do this automatically when you select the defog/defrost setting of the heating system.
Unfortunately, it doesn’t work for defrosting the outside of the windshield. It’s actually detrimental, as it reduces the temperature of the air coming out of the windshield vents. Many vehicles allow you to turn off the A/C in defog/defrost mode for this reason.
I can leave the selector on my 1/2 ton to defrost with the fan on high and use the remote start to defrost inside and outside. My wife’s SUV won’t allow the blower to run on remote start.
Or…just wait till the sun comes up and warms the windshield. Most days we didn’t roll out of the overnight spot till 10am.