Artemide - Tizio 50 years Limited edition - design desk light

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.