Objective for calculation of Thermal load (heat gain) of room is done for the selection of right size of air conditioner, in order to achieve optimize energy at required temperature, humidity and proper distribution of air. Heat gain into the room depends on many factors such as orientation of the room, latitudes, size of room, number of person, electrical equipment, materials used in construction of wall and roof, numbers of doors and window and their sizes. Cooling Load Temperature Difference / Cooling Load Factor (CLTD/CLF) method based on ISHRAE (Indian Society of Heating, Refrigerating, and Air-Conditioning Engineers) Handbook is used for determining heat gain in the room. In this paper load calculation is done for the library. Through the calculation it is obtained that total heat gain in the library is about 165880.977 Btu/hr (48614.91 W)
