It would seem to me that as a nation, we use a lot of fuel to "warm up' a vehicle to defrost windshields. I would think that auto manufacturers could install electric heaters that would provide immediate heat to defrost windshields, saving on the amount of fuel used to defrost windshields. Perhaps one that ran off of a supplemental battery and could be turned on remotely to run 10-15 minutes. Drivers could start their vehicle and go without having to waste fuel defrosting a windshield. I would think this would be a big selling point for automobile manufacturers who did this.