The paper presents a case study in project based learning. The issue of energy efficiency of lighting was combined with environmental effects, both in terms of electromagnetic interference generated and in terms of the waste disposal risk. Three types of light bulbs are described in the paper: incandescent, fluorescent and LED bulbs. A method of evaluating the effectiveness of illumination in an image histogram is proposed. A test stand that measures electromagnetic disturbances generated in the network by bulbs is presented. All the work was carried out involving students in projects. At the end of the paper, results of a brief survey of this work are presented.