A method for controlling the temperature in a vehicle cabin, while the vehicle engine is turned off, includes the following steps: importing a State-of Charge information of a vehicle traction battery, an outside temperature, and inside temperature of the cabin into an electronic controller; calculating a normal electric power required for operating an HVAC system in a Normal mode; calculating a maximum operation time of the HVAC system in the Normal mode based on the State-of-Charge information; displaying the maximum operation time on a display; reading an operator input selecting one mode of at least the Normal mode and a first Eco mode of the HVAC system, wherein in the first Eco mode the HVAC system operates at a reduced electric power compared to the Normal mode; and operating the HVAC system in accordance with the operator input. A suitable HVAC system includes an appropriate user interface.