Using solar energy an office is heated from the floor and a thermal comfort analysis is performed for Ankara conditions. Solar energy is collected by flat-plate collectors in a storage tank. The thermal comfort analysis of the office is performed using Fanger's method. In this method the thermal comfort is affected by environmental and individual parameters; air velocity. humidity, temperature, radiation temperature, activity and cloth resistance. Measurements arc taken at 0.2 m, 0.6 m, and 1.0 m heights beside floor temperature. The experimental results and the individual data are used to calculate the Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD). A computer program is written in FORTRAN to calculate these parameters using the experimental, individual data and the results arc presented as PMV diagrams. The results indicate that the thermal comfort can be provided with such a heating system. The PMV values range between -2.00 to 2.00.