The air conditioner has main air conditioning unit (8) with a heat exchanger (10), and electrical heating device (12) which supports heat exchanger. An auxiliary air-conditioning unit (14) comprising electric heater (16) is arranged in remote location in a passenger compartment. A controller is provided to heat passenger compartment using alternator output from electrical heating devices so that thermal comfort of each occupant to different seat positions are optimized according to predefined priorities. An independent claim is included for method for controlling air conditioner.