In recent years fuel consumption of passenger vehicles has received increasing attention by customers, the automotive industry, regulatory agencies and academia. However, some areas which affect the fuel consumption have received relatively small interest. One of these areas is the total energy used for vehicle interior climate which can have a large effect on real-world fuel consumption.Realistic combinations of energy saving measures were evaluated regarding the total energy use for vehicle interior climate using a one dimensional (1D) simulation model. The 1D simulation model included sub models of the passenger compartment, the air-handling unit, the Air Conditioning (AC) system, engine and engine cooling system. A test cycle representative for real-world conditions was developed. The test cycle included tests in cold, intermediate and warm conditions and the results were weighted with the estimated use in each condition.In the investigated case the average electrical power was decreased with 50%, primarily through a new blower control unit. The mechanical compressor power was decreased with 45%, primarily through less engaged AC-system. In addition the energy flow into the passenger compartment, for cooling and heating, was decreased with almost 20%, largely through increased insulation of windows, shell, ducts, and decreased interior mass. All these savings were made without decreasing the potential of thermal comfort for the passengers.When the most beneficial energy saving measures have been implemented further reductions of energy use for the climate control system will become very challenging. To achieve additional energy reductions, with this type of system, the airflow has to be reduced or more energy must be recovered from the air. Many challenges with these measures can be expected.