The label proposed by the German economy ministry earlier this month is modelled on the well-known energy efficiency label for household appliances. “The draft label is reasonable and could serve as a model for a European label,” a spokesman for the German car industry association told ENDS.

While welcoming the concept, green and consumer groups are critical of the energy efficiency categories being based on a combination of a car’s CO2 emissions and weight.

Environmental group VCD argues that a car’s weight is an unsuitable parameter for an energy efficiency label. If two cars have the same weight, the one with lower emissions ends up in a poorer energy efficiency category, consumer group Verbraucherzentrale Baden-Württemberg claims.

The VCD also laments that electric cars would always fall in the best efficiency category, regardless of the type of electricity they use. The green group has developed its own label.

Meanwhile, Germany’s environment agency, the UBA, has recommended the use of CO2 in mobile air-conditioning systems. Refrigerant tetrafluoropropene, also known as HFO-1234yf, is favoured by the car industry for being globally accepted. The UBA and the car industry disagree on which new refrigerant has the lowest climate impact overall.