Thermal comfort is a key aspect of indoor environmental quality in buildings, affecting the well-being, health, and efficiency of occupants. In the era of sustainable construction, optimal heating system design and effective control of microclimatic conditions are becoming increasingly important. The aim of this study is to compare the impact of two types of surface heating – underfloor and wall-mounted – and application of solar shading on the perception of thermal comfort in indoor spaces. Experimental studies were conducted in two comparable laboratory rooms, one equipped with external venetian blinds, while the other had no solar shading. In both rooms, sensors were placed at a heigh of the human centre of gravity in seated position–0,6 m, to record microclimate parameters. The measurements included, among others, air temperature, relative humidity, and air movement velocity. Thermal comfort was evaluated using the PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfied) indices, which are widely used indicators of indoor environmental quality. In both rooms, at a set temperature of 24 ℃, occupants experienced slight thermal stress outside periods of direct solar exposure. During intense sunlight, in the room without blinds, the PMV index reached high values, indicating strong thermal stress (PMV > 2). In contrast, the room equipped with blinds maintained more stable microclimatic conditions. No significant differences in achieved thermal comfort were observed between underfloor heating and wall-mounted heating. This study provided valuable insights into the effectiveness of thermal condition control in surface-heated spaces, depending on the presence of venetian blinds. The findings may contribute to optimizing HVAC systems in residential and commercial buildings, improving occupant comfort and energy efficiency.