[DeRock]

A resistive heater directly converts electricity to heat, whereas a heat pump instead moves heat, from the outside to inside of your car. The heat your car gains is reflected by the heat the outside loses. In that way, they can be 300-400% “efficient”, because we do not care about the outside air around the car getting a little bit colder.

[jhoechtl]

> whereas a heat pump instead moves heat, from the outside to inside of your car.

I completely forgot that the energy of the outside air is used, that explains it of course.