Infrared heating is increasingly being used in buildings either as the stand-alone heating system or in combination with a water-based heating system, for example to cover peak loads. A standardized test procedure has been defined and implemented in order to be able to compare heating systems and present them in energy calculations. For infrared heating, this is DIN EN IEC 60675-3, which describes the test procedure for determining the radiation efficiency. This measurement method was realised in the Combined Energy Lab at TUD Dresden University of Technology and applied to more than 100 different heaters. The paper will present the test setup and the measurement data. In addition, various influencing variables such as the type of installation (wall/ceiling) and the effect of the temperature of the surfaces surrounding the room on the radiation efficiency will be discussed, the error tolerances will be described and an assessment of the laboratory measurement compared to practice will be given.