In an effort to improve transparency, on initiative of the European Commission a new, additional test cycle on consumption caused by the car air-conditioner currently is being developed: the MAC (mobile air-conditioning) Test Procedure. Graz University of Technology and TNO are in charge of the project since 2009. In the ongoing two-stage pilot phase the consumption of 30 different vehicles on different chassis dynamometers initially had been measured in a ring measuring both when idling and at 50 and 100 km / h with the air-conditioning system switched on and off. With the help of several sensors, the air temperature is measured inside the vehicle, during the outflow and in the test stand (see chart). In spring 2013, the pilot phase presumably will be completed.

In the future the consumer could be kept updated on the measured consumption values in two ways: On the one hand, the additional consumption by the air-conditioning could be integrated in the official fuel consumption figures or offset via bonus/malus regulations. The other option would be a detailed listing of equipment efficiency (e.g. in the form of a label). As positive as the initiative of establishing a consistent test procedure is, there are criticisms on the planned EU MAC test procedure:

• The measurement method only allows a relative comparison of various types of air-conditioning systems. Reliable information about the absolute (and realistic) consumption cannot be given.
• Solely the efficiency of the air-conditioner will be considered. Other possible measures of heat management are going to be left out – except for a correction factor for heat-reflecting glazing.