Abstract: Thermal comfort is one of the main aspect of human life due to the period of time each of us spends inside of the enclosed room on one hand as well as the health issues connected with the sick building syndrome on the other. Presently, the international standards are based on the Fanger model with calculations of proper indexes according to the inside air parameters as well as characteristics for room users. The paper presents the verification of Fanger model with experimental data obtained from research conducted in 6 classrooms of an intelligent, educational building. The measurements were acquired by means of Testo 400 meter where air parameters such as temperature or humidity were collected. For other evidence the questionnaire was prepared, where respondents presented their thermal sensation together with the information of their clothes present thermal insulation. The results proved that the Fanger model is not precise, since the findings calculated with the international standard differ from those obtained from the questionnaires.