Karman - Ceraunavolta E glass - Composition's element

The luminous efficiency is the ratio between the intensity of the emitted light and the electric power absorbed by the lamp and it is measured by the ratio lumen/watt. The ratio expresses the luminous efficiency and the energy consumption. To an high luminous efficiency corresponds an high class of luminous efficency and therefore a lower energy consumption. The UE energy label show the annual consumption in kWh. The classificataion occurs in letters from A++ to E, where the lettere A++ corresponds to a consumption less than 188 kWh and the letter E corresponds to a consumption higher than 781 kWh.