Analyzing building loads and energy-efficient retrofits is crucial for effective energy management and sustainable development. Strengthening the identification and analysis of factors that impact energy consumption is informative for devising appropriate measures. In order to address the current limitations in analyzing building energy consumption, the present study proposes a combination of the arc elasticity analysis method with CO2 storage technology. By introducing sensitivity and arc mean elasticity indices, the cooling and heating loads of building energy consumption can be analyzed. Subsequently, a CO2 refrigeration system and compression process can be designed to optimize the storage of CO2 and facilitate its role in energy conservation and reduction of energy consumption. Thus, the research aims to fulfill the potential of CO2 in promoting energy efficiency and reducing consumption. The study utilized software simulation and experimental analysis to examine the impact of the proposed method. The findings revealed a positive correlation between the heat transfer coefficient and the building's annual heat load. In addition, the maximum data variation of the building's cold load was a mere 0.05 per cent, and the relative discrepancy between the software simulation and the actual load values was less than 10 per cent. The exterior building's total cold load value showed a difference of more than 25 per cent when cooled with CO2 intervention compared to the non-intervention result. Furthermore, the building's maximum load reduction reached 3.4 per cent when uniformly varying the thickness of the insulation layer from 40 mm to 100 mm. The proposed method demonstrates a positive impact on building energy sensitivity analysis. Its energy loss design for various parts of the building could offer useful references for practical engineering designs.