The thermal balance of vehicle cabins when only an internal combustion engine was used was an insignificant element of the vehicle design. The excess thermal energy on board did not require energy saving. Only the cold start was slightly problematic. However, it could still use a combustion heater that quickly warmed up the cabin. In purely electric cars, each use of electricity stored in the battery shortens the vehicle's range. Three types of heating are used in this case: a) an electric air heater; b) an electric heater for the liquid cooling the drive components; c) a heat pump receiving heat from the drive components, also temporarily supported by an electric air or liquid heater. The use of a heat pump is the most promising and is also used in cheap city cars (e.g. Renault ZOE). The source of thermal energy for a heat pump is: a) vehicle drive engine(s); b) AC/DC converters – charger, DC/DC – charger, DC/AC – motor inverter; c) battery. In cheaper vehicles, air cooling is partially used; currently, a mixture of antifreeze fluids is used. The article presents a calculation example for a city bus cabin.