in Canada they use these things...I have copied and pasted from my friends answer to the question ....what do you mean plug in the car??
"because vehicles won't start in intense cold, as the oil in the oilpan freezes into a block of black ice, we install block heaters to keep this from happening. a block heater is a kind of electric blanket for an engine. it provides enough heat to keep the oil in a liquid state, so the engine can turn over to start. as heat production requires a lot of electrical power, this can't be provided by the vehicle's battery without draining it, so the block heater has a short electrical cord attached to it for plugging in. this isn't needed in the summer months, so cords are generally tucked up out of the way then, to protect them. parking stalls in northern cities usually have numerous electrical outlets designed into them for this reason. it's very common (especially early in the winter) to see someone who's rushed off to work, not quite awake yet, with an extension cord dragging from their vehicle as they go, because they forgot to unplug it before driving off."
bit safer than lighting fires anyway.
I wouldn't know my new to me car is in the garage for the forseeable future anyway. unless somebody has an electric power steering motor for a skoda fabia lying about??