Abstract The better improvement on the system performance of R-410A inverter air conditioner was performed. The proper operating strategies of whole system with evaporatively cooling unit were investigated experimentally and numerically. The adapting system was tested by varying of frequency, water flow rate and spraying temperature. Fortunately, the combined system obtained an extended frequency range of 30–90 Hz properly. A longer capillary tube length of 887 mm with a lower optimal charge of 1.1 kg was chosen for the water temperature closed to inlet wet-bulb temperature. The water injection rate of 200 l/h obtains the best COP at a low frequency range while the flow rate of 100 l/h being at a high frequency range. Finally, the integrated model and the leakage inventory model were developed to predict the performance and the optimal charge, respectively. It can be concluded that the proposed models give a satisfactory agreement with test data.