When you turn on your defroster fan, within a minute or two, it starts to clear a little area at the bottom of the iced over windshield. Yet, the car engine is not yet warmed up, so it’s blowing cold air. How does blowing cold air on the inside somehow start to break down the ice on the outside of the glass??
I think I have seen some cars with a blower vent on the outside hood, and this would make more sense as there is direct air blowing onto the iced glass. Even though it’s still just cold air. But, most cars don’t have outside vents and just the inside vent. How does this work? I understand how WARM air from the inside would conduct through the glass and melt the outside glass, but not cold air when the car has just started up.