The efficiency requirement of room air conditioner (RAC) has became stricter and stricter with the development of global environment consciousness. The efficiency evaluation method of RAC has been updated from single working condition to aunnal performance factor (APF) with multiple working condition. Performance evaluation method of compressors must be changed accordingly which account for main energy consumption of RAC. Compressor efficiency of annual performance (COAP) is proposed to evaluate the efficiency level of inverter compressor which is applied in variable speed RAC with multiple working conditions. Actual operation efficiency can be indicated by COAP because inverter compressor performance is considered according to COAP. In order to simplify test procedure of COAP

standard test conditions and its weight are generated .Then the effect of efficiency curve of inverter compressor on COAP is discussed . Finally examples with this method are illustrated for compressor matching and design optimization.