Currently, the estimation of annual energy-saving performance of Energy Performance Contracting (EPC) projects is still at the operating level of each individual project, lacking a systematic summary. This paper studies the regression relationships of revamping cost in terms of annual energy-saving quantity and annual cost saving of EPC projects. The regression results show that there are statistically significant correlations in the above relationships in the nine subsectors investigated. These results contribute to EPC investment decisions and trust relationships between Energy Service Companies (ESCos) and energy-consuming units (ECUs). Then a multiple linear regression model of revamping cost is set up to analyze its influencing factors. The model indicates that the subsector the sample belongs to, financing, registered capital of the ESCo, and contract period have significant effects on revamping cost. Finally, advice for promoting investment in EPC projects is given.