I've had the same thing happen here in Cleveland on my coupe. Whenever I know the temp will drop below freezing, before I shut the car off for the night, I leave the heater controls set to 80, turn the fan to high, and turn the airflow to the dash vents , and then aim the drivers side and pass side vents right at the side windows. Usually after 10 minutes it will be warm enough to start to melt the ice on the glass, but once I had to do the 2nd remote start. Of course this only works if you have the remote start. Otherwise the deicer is best, and SimplyRed is right, hot water can shatter the tempered glass.