The CO₂ efficiency class indicates how a passenger car compares to other cars in the same weight class.
How is the efficiency class calculated?
Which efficiency class a car gets depends on CO₂ emissions and weight. A reference value for CO₂ emissions is calculated based on the vehicle weight using the formula specified by the legislator. This reference value serves as a benchmark for comparing the CO₂ emissions of a specific vehicle – taking into account its weight – with the CO₂ emissions of an “average” new car. The more a car weighs, the higher the reference value. The reference value calculation formula is based on the weight distribution and CO₂ values of new passenger car registrations from 2008.
To determine the efficiency class, the actual CO₂ emissions of a model must be compared with the determined reference value. The vehicle is assigned to one of the CO₂ efficiency classes according to the deviation from the reference value. Classes A+ to D are awarded to cars whose CO₂ emissions are lower than the reference value. Vehicles whose CO₂ emissions are equal to or exceed the reference value are assigned efficiency classes E, F or G.
A car that emits 1.500 kilograms (e. B. upper compact or Golf class), has a reference value of 171 grams of CO2 per kilometer (g CO2/km). At this weight, a car must emit less than 108 g CO2/km to be rated A+. If the CO2 emissions are 120 g/km, this corresponds to class A.
A car that emits 1.000 kilograms has a significantly lower reference value of 126 g CO2/km. To achieve class A+, the car must emit less than 80 g CO2/km. A CO2 emission of 120 g/km corresponds to class D.
Why is the CO₂ class dependent on weight?
The CO2 efficiency class provides information on how much CO2 a vehicle emits in relation to its weight. This has the advantage for consumers that they can compare CO2 efficiency within a vehicle segment. If the customer wants to buy a small car, for example, it is important for him to compare his desired model with other – usually similarly lightweight – small cars. After all, he doesn’t want to compare apples with oranges, i.e. small cars with luxury-class cars.
Such a relative approach to efficiency labeling is also common for other products. For refrigerators, for example, the energy efficiency class is calculated u. a. depending on the cooling volume. In the case of passenger cars, weight is a pragmatic parameter for calculating CO2 efficiency, since fuel consumption and thus CO2 emissions rise with increasing weight.
The German Energy Agency (dena) provides information in the scope of this information platform on the transport and mobility transition. In addition, manufacturers and dealers will receive information on the implementation of the amended Passenger Car Energy Consumption Labelling Ordinance (Pkw-EnVKV). The statements made in this information portal have been coordinated with the German Federal Ministry for Economic Affairs and Energy (BMWi) and other expert stakeholders and reflect their common views. These are general indications that are not legally binding. For specific questions, if applicable. to obtain legal advice. dena accepts no liability for the accuracy of the results calculated using the online tool for creating a car label. The decisive factors are u. a. the manufacturer’s specifications.