Glazed roof has a convenient place to receive solar radiation, however its bad thermal mass affects the indoor thermal environment and energy consumption. In the present work, the effect of glazed roof filled with phase change material on its thermal mass was experimentally investigated and compared with conventional glazed roof. Experiments with different PCM melting temperatures, PCM layer thicknesses and glazed roof slopes were performed to analyze their effect on the energy consumption and dissatisfaction rate of indoor thermal environment. Also, a general economic analysis was performed to assess the viability of glazing units containing PCM. The results show that the energy consumption of glazed roof filled with PCM is significantly less than that of air, and up to 47.5% of energy saving can be achieved. Payback period can be reduced to 3.3 years by proper selection of PCM melting temperature. Increasing the melting temperature of PCM can effectively decrease the temperature of internal surface of glazed roof, but has a slight influence on the dissatisfaction rate of indoor thermal environment. Increasing the thickness of PCM layer decreases the peak temperature of internal surface of glazed roof and indoor chamber, the energy consumption and the dissatisfaction rate. The highest energy consumption and dissatisfaction rate are obtained at 20 degrees of the inclination angle.