During the past several years numerous products designed to reduce energy consumption by lighting systems have appeared in the market. These products may increase system efficacy, reduce light by a fixed amount, or dynamically dim lamps over a wide range. However, these systems could have a profound effect on utility loads. This paper deals with the performance of a number of energy saving ballasts under varying voltage levels. Voltage changes may affect the ballast efficacy and may introduce harmonic contents into the electrical system. Tests were conducted to determine the electrical and illumination characteristics of three energy saving lamps as a function of varying voltage levels. These characteristics are the power, reactive power, power factor, and the illumination. Harmonic contents were measured at various input voltage levels via the Bonar harmonic analyzer. All the lamps exhibited less than 5% of total harmonic distortion although individual harmonic contents differed slightly.