The paper focuses on important elements i.e. appropriate lighting conditions at workstations and the assessment of subjective productivity as a function of indoor environmental parameters, using the example of students in the intelligent building “Energis” at the Kielce University of Technology, where an experimental study was performed. A group of volunteers completed questionnaires about their subjective feelings related to lighting conditions in lecture halls at different times of the year and assessed their current productivity. Accurate physical measurements of illuminance with a high accuracy microclimate meter were carried out. Comparing the statements of the room users with the measurements allowed conclusions to be drawn about the conditions provided in the intelligent building related to lighting, as well as the impact of the working environment on the productivity of the room users. The findings provide valued information on lighting conditions in modern, intelligent buildings, which are becoming increasingly common around the world, for various purposes such as office, educational and other public buildings, so that appropriate indoor conditions can be used to optimise productivity and efficiency.