We often forget the indoor environment that has a major impact on our well-being and health. In addition to negative effects on people we also have negative effects on building health and the building envelope. In this thesis I have focused on the parameter of relative humidity and air temperature, which strongly affect the user and the building. By identifying the possible causes of excessive humidity, I have proposed remediation measures at the site of the Heroja Janeza Hribarja Primary School in Stari trg pri Ložu. For data analysis, we record critical points of building envelope (indoor and outdoor) with thermal camera and digital camera. We also made measurements of relative air humidity and air temperature in the art classroom and distributed questionnaire among the employees at the school. With the TEDI software I have checked the appropriateness of the structural complexes with legislation (PURES 2010). After analysing and comparing results, I have come to the conclusion that the majority of employees feel discomfort in the area where they are located. The building insulation is poor and inadequate, which is also evident in the thermograms with visible thermal bridges. Thermal flux of the structural complexes does not meet the requirements given by Pravilnik o učinkoviti rabi energije v stavbah (PURES 2010). The upper limit of relative air humidity (60%) in the art classroom is often exceeded. Rooms in the buildinga are also poorly ventilated. A thermal insulation is recommended and so is the use of thermostatic valves and other remediation measures presented in this thesis.