Energy labels include data on fuel consumption and CO2 emission of the new car. Energy labels range from A to G; the A label applies to the most fuel-efficient, the G label for the least fuel-efficient types of cars. When car energy labels were introduced, authorities have opted for a labeling system reflecting the relative fuel-efficiency. A car with a green A label is fuel-efficient relative to other cars in the same size category. A car with a red G label is not fuel-efficient for their size category. Back to article