Thermal comfort is the condition of mind that expresses satisfaction with complex thermal factors. There are three main factors that can affect the human comfort, which must be considered by engineers before designing progressive indoor technologies; effective temperature, relative humidity and air motion. Building occupants are a rich source of information about indoor environmental quality and its effects on comfort and productivity. Subjective evaluation of indoors is an important part of assessing the quality of the indoor environment. The problems with perceived thermal conditions occur in the buildings using new indoor technologies. Generally it is not easy to arrange good thermal conditions indoors. A large number of people perceive thermal discomfort caused by high or low indoor temperatures. This problem was studied in the selected public building mostly with open space offices. The office buildings broadly are characterized by a large area of glass surfaces, which are significantly affected by external climatic conditions and sunlight. The paper deals with the perceived thermal indoor conditions in the open space offices where the low temperature heating and high temperature cooling were used. The questionnaire for subjective evaluation was used. The questionnaire includes the following parameters: level of indoor acceptability from thermal comfort, air movement, air quality, and air humidity. The thermal conditions were perceived as slightly warm during the winter operation. On the other hand during the summer operation were the conditions perceived as neutral. The other studied parameters were evaluated as acceptable for both periods.