If fixing the heater core on your car isn't possible before you get into cold weather, a portable car heater is a viable option. However, there are a few things to keep in mind:
What it comes down to is that while even the best electric car heater will not replace a broken car heater, that doesn’t mean you have to drive around icy cold.
Since residential space heaters heat relatively large volumes of air, you should be able to use one to heat a car. And while most any space heater will put out enough heat to make you toasty warm in no time, there are two potential problems with this solution.