Investigation of energy efficiency index for indoor LED lighting units

The energy efficiency index (EEI) is an important factor used as an indicator either for building energy consumption or electronic device performance; it allows one to select effective devices that save energy. This work studies the performance of different types of LED lamps used in indoor lighting, the lamps currently available in the Egyptian market have been tested according to their photometric and electric parameters, namely: luminous flux, power factor, and EEI. Three different brands E, T, and V have been chosen with the nominal powers 9, 12, and 15 W. The results showed that both 9- and 15-Watt lamps have the same EEI values as 0.14, 0.13, and 0.12 for T, V, and E lamps, respectively, whereas 12-Watt lamps have EEI values of 0.16, 0.13, and 0.13 for T, V, and E lamps, respectively. The experimental testing of these lamps revealed that all the lamps have the same EEI class (A+) regardless of the nominal power. The results also revealed a relationship between the power factor and EEI: as the power factor increases, EEI increases, too. The expanded uncertainty in luminous flux has been calculated.