Windows completely frost up

Hello everyone I have a 2008 base model aveo with 145000km. Recently all the interior windows are frosting up so much they have to be scraped from the inside. The car still produces good heat but has to be run on full defrost with the fan on high to keep them almost clear. Front windshield drivers and passenger windows will clear but rear windows don't ever. Checked the coolant today and it was almost completely out, I'm unsure of how long it was empty for. Refilled the coolant and checked the thermostat for visible leaks but found none. Will park on news papers tonight looking for any leaks. Any ideas on what to check next. Thank you!

Mine did the same thing. Nothing I could would keep the rear windows clear.

Don't breath....well I am kinda not kidding. Considering how dry the air is in Canada, you are the only person putting moisture in the air. So considering you can't stop breathing. Get the car dry without you in it. So warm it up and wipe down the insides, then drive. Make sure your AC is running that will keep the air dryer.

If the heater core is leaking, you will be able to get frost on the inside, but you will also have an oil slick looking build up on the windows. Plus it will smell like coolant. I would doubt that is the issue here.

I get this once in a while, typically when it rains before it snows. A day or two of the rain and moisture build up in the car, then you have frost on the inside. It usually goes away after a day or so of use when its dry again.. But if you fill the floor boards with snow from walking out to the car, etc. it will come back.

The only real solution here is warm the car up and run a dehumidifier to suck out the moisture.

This might seem like a no-brainer, but make sure the fresh air- recirculation switch is in the fresh air mode. Nothing will fog up the glass faster in a cold climate than having that switch on recirculate. The moisture from your breath stays in the car, then by the next morning, you have frost on the inside of the windows.