In built environments human thermal comfort is achieved by maintaining a heat balance between the human body and the environment, such as walls and other surfaces, by radiative and convective heat transfer. Glazing systems have distinctly different thermal and optical properties from the walls, which severely affect the human thermal comfort in a room. The comfort of an occupant can be adversely affected by the presence of significant hot or cold windows. Window surface temperatures often fluctuate much more than those of other surfaces in a room and occupants experience discomfort as a result of radiant heat exchange with window surfaces. In this paper a numerical simulation tool is developed to assess the performance of different types of glazing on thermal comfort distribution parameters inside a room. The basis for the program is Fanger’s model of Thermal Comfort. The basic parameters used to evaluate are the Mean Radiant Temperature, PMV and PPD. To calculate the MRT and its distribution in the room, ASHRAE guidelines are employed. Based on the results the effect of the glazing is studied for the required climatic condition. The effect of non uniform radiation asymmetry created due to a particular type of glazing is incorporated. The simulation is done for radiant temperature inside the room considering single, double, triple and quadruple with low e values. Finally the program is also validated using a case study in a non conditioned room space with respect to Chennai climate (Hot humid).