An electricity generating and air conditioning system including an engine, a generator connected to an output shaft of the engine to generate electricity, an air conditioner, which uses the electricity generated from the generator and includes a compressor, an indoor heat exchanger, an outdoor heat exchanger, and an expansion device, and an exhaust gas waste heat recovering device to recover heat of exhaust gas discharged from the engine and to transfer the recovered heat to a refrigerant passing through a discharge line of the compressor. The electricity generating and air conditioning system has an advantage in that an enhancement in heating performance is achieved.