The application of the energy demand side management (DSM) solutions to decrease the cooling load and facilities needed to provide comfortable air condition in office buildings in the hot and humid climate is presented in this paper. The main goal is to demonstrate a new approach, through quantitative results obtained from calculations performed in a real office building complex in Ahwaz, south west of Iran, in the building energy management based on the energy DSM. Upon implementation of energy DSM practices, the real cooling load demand for the building air conditioning decreases considerably which substantially decreases the capital needed for buildings air conditioning systems construction and maintenance, and, also the damages to the environment. Different buildings energy DSM practices are introduced, classified, and their effect on decreasing the cooling load requirements are calculated and discussed by accurate investigation of local, technical and climate conditions. The overall demand for cooling decreased about 30% which demonstrates the importance of DSM practices for building energy management