China has implemented substantial measures to curb energy consumption and mitigate environmental impacts in recent decades. Within the residential sector, rapidly growing household appliance ownership has significantly increased electricity demand, necessitating more effective energy conservation policies. This study examines refrigerator sales in Beijing as a case study to assess the efficacy of current subsidy policies in promoting energy-efficient appliance purchases. Specifically, we selected ten refrigerator model pairs from six major brands, each pair featuring comparable functionality but differing in energy efficiency grades (EEG). Using an integrated analytical approach combining the net present value (NPV) difference method and the Electrical Engineering Coefficient Conversion Method, we evaluated policy effectiveness through comparative analysis of NPV differences and dynamic investment payback periods (DIPP). Our findings indicate that economic benefits primarily accrued at EEG2 level, suggesting two policy recommendations: (1) phasing out subsidies for EEG2 refrigerators, and (2) increasing subsidies for EEG1 models by up to 24% to enhance policy effectiveness.