Rough metrics say idling can consume anywhere from 1/3 of a gallon to a gallon per hour of idle time. Taking the worst case, and why not because it's cold, and

Rough metrics say idling can consume anywhere from 1/3 of a gallon to a gallon per hour of idle time. Taking the worst case, and why not because it's cold, and people may be inclined to do more than idle their engine, means roughly an hour per gallon of fuel. Some ICE cars may only idle for a few hours, others a lot more, depending on what's in the tank. Best move is to pulse the engine. Start up, idle until the vehicle is really warm, shut down and repeat every other hour or so, depending on the cold and what people have to stay warm with.