Light pipes are daylighting technologies that permit the entrance of skylight and sunlight in spaces with no or little daylight availability. Various different versions of this system have been developed, aiming to maximize the performance of the light pipe or to combine the function of daylight guidance with artificial lighting or natural ventilation. Also, various researchers have developed methodologies and algorithms, both theoretically and experimentally, for the calculation of light pipe performance. This paper includes the description of the research performed in the framework of the European project HERB: Holistic energy-efficient retrofitting of residential buildings. Up to date, the study has resulted in a methodology, for the easy and quick calculation of the interior illuminance provided by light pipes in rectangular rooms and in a lighting system, which incorporates a light pipe with LEDs and smart controls. Recently, an experimental setup has been realized, with a real-scale model of the designed system, in order to monitor its lighting and energy performance and to test the accuracy of the developed calculating method. The paper describes the experimental procedure, presents the findings and discusses the comparison of the calculated and the experimental data.