Extremely Foggy Windows... Bad Heater Core?
While driving home last week, I had the heat/defroster turned on, & within 2 - 3 minutes there was so much condensation on my windows and windshield that I could barely see anything. I stopped to clean them off using glass cleaner, and within 2 more minutes of continuing my commute home the windows were fogged up again, like a watery film on the glass. Cleaned 'em off again, left the heat off this time, and they were fine. After a few minutes of driving in 15 degree weather and not being able to feel my hands, I turned the heat back on (low setting). Boom, windows were fogged up again.
Looked up what it could be, and everything points to a bad heater core, except for all of the other common symptoms. My heat works fine (nice and hot), I'm not noticing a loss of coolant, I'm not noticing any wet spots on the passenger side floor or under the car, I don't really smell any fluids, etc.
So is the heater core still the culprit? Seeing how big/difficult of a project it is to replace it, I was wondering if anyone can provide any other possible causes or fixes before begin disassembling my entire dash.
Thanks in advance!