Preventing frost on inside of windshield?

Nov 20, 2013
Eastern Wa.
Periodically I'll get frost on the inside of my windshield in the winter. I assumed it was worn seals. I learned a trick that seams to work for me. After getting home from work and locking up for the night I roll down the window and wait for a minute or so and roll it back up. Letting in the cold air keeps the moisture from building up and freezing overnight.
Thank you for the tip. I'm going to try it.
Maybe just leave the door open minute or two while I go to the mailbox or something. Just get the cool dry air in, eh?
Could be worn weatherstripping is letting water creep in, which is potentially fixable, or less so is snowy footwear leaving moisture behind. Either way, I'd put a dehumidifier in it to dry it out as much as possible because long term that can cause mold. I mean the mains powered, appliance type dehumidifier if you have one.

Another crazy thing you could try is a big bag of rice in a burlap sack, or silica desiccant. Throw it in the vehicle, then once (or ideally before) your windows start frosting up again, take it out and put in the oven for a while to drive the moisture out, then reuse.
I always blast the heat inside the car about 3 minutes before I arrive at my destination in cold weather. The ~80f air inside the car absorbs a lot of moisture. I keep the driver side door opened a bit when I arrive/ am parked to vent the humid air out of the car. The interior including the windows stay dry and frost free that way.
You have a water leak letting moisture in somewhere-the F-450 does that due to a shaky windshield seal if it rains a lot before a cold snap. Seems like cracking windows & running the defrost full on gets it dry fairly quickly, cold air warmed up can pick up a lot of moisture.