The master's thesis deals with ten multi-apartment buildings from the area of Slovenia, which date back to the period from the Second World War until today. For these buildings, the first part uses the static method of determining the daylight factor (D) for estimating the illuminance with daylight at the level of living areas and bedrooms in selected two-bedroom apartments. The method and results are adapted to the verification of the requirements of the Standard for the Daylight of buildings (SIST EN 17037: 2019), in accordance with the substantive baselines of the standard in Appendix A and Appendix B for the determination and verification of the target daylight factor (DT) and the minimum target daylight factor (DTM). In the second part, the work focuses on verifying and determining the correlation between the geometric and optical properties of the space / building in relation to the results obtained from numerical analyzes. For this purpose, control models are determined to monitor the various influences of individual geometric and optical factors on the daylight of the room. Based on the results of the analysis of illuminance for control models, a method is given that enables the determination of average values of the daylight factor and it is based exclusively on the geometric and optical properties of the surfaces of the room / building. The method was tested on appartments from a set of ten considered multi-apartment buildings, the results are given in graphical form by comparison of the values of daylight factors from numerical analyses. In the final part of the master's thesis, on the case of two buildings, a verification assessment of the impact of energy and major renovations of the building envelope on the illumination of interior spaces is performed.