Abstract: To make full use of the flash steam generated from technology condensation water of the primary department in a cigarette factory, a return water heating system with dual heat source for the air conditioning system was designed. The designed system consists of a condensation water reclaiming device, a flash steam heat exchanger and a steam heat exchanger. The flash steam in the condensation water reclaiming tank was collected to heat the return water of the air conditioning system through the flash steam heat exchanger and steam heat exchanger. Once the water reaches the pre-set temperature, it is directed to the combined air conditioning unit for air heating. The designed system was tested on the air conditioning system in the primary department in Changde Cigarette Factory of China Tobacco Hunan Industrial Limited Corporation, and the results showed that the dual heat source system saved 4.92 tons of steam per working day. This technology provides a solution for reducing energy consumption in cigarette production.