This paper reports a novel application of an air source heat pump system for cooling, heating and domestic hot water production in Shanghai for a typical apartment. The appliance can supply five functions as space cooling, space cooling plus domestic hot water, space heating, space heating plus domestic hot water, and domestic hot water only. In winter, the system was aim to solve the central heating problem in the area of Yangtze river basin and the operating performance under specified weather conditions. The system was combined with a Low-H2O heat exchanger to decrease the supply water temperature for saving the energy. The heating return water temperature was set at 30°C, 35 °C and 40 °C for heating in winter which lower than the conventional air source heat pump system. When the inlet temperature was set at 30°C, 35°C and 40°C, the power consumption was 27.18kWh, 39.84 kWh, 51.48 kWh, respectively. The power consumption of the system increased 89.2% at the inlet temperature of 40°C and 46.6% at the inlet temperature of 35°C compared with the one at the condition of the inlet temperature of 30°C. When inlet temperature increased from 30°C to 40°C, the COP of the air source heat pump decreased from 3.50 to 2.22 with the percentage of 36.5% at the conditions of the outdoor temperature of 6-7°C. The indoor temperature of the apartment was at the range of 19.4 to 20.9°C with the conditions of the inlet temperature of 30°C and the average temperature 5.1°C.