Improving HVAC Refrigerant Charge Value Estimates for Residential Systems

The report focuses on updating refrigerant charge values for residential HVAC equipment to improve the accuracy of the Refrigerant Avoided Cost Calculator (RACC) Tools used in California energy efficiency programs. Conducted on behalf of the California Public Utilities Commission (CPUC) and CalNEXT, the study addresses the transition to low-global-warming-potential (GWP) refrigerants, such as R-454B and R-32, mandated by state and federal regulations. These refrigerants replace the high-GWP R-410A, which is being phased out due to its environmental impact. The research team collected refrigerant charge data from 19 manufacturers, analyzing 736 systems across various residential HVAC equipment categories. The study identified significant differences in refrigerant charge values based on equipment type, capacity, and refrigerant type. The report recommends updating the RACC-FSC_v3.1 Tool to reflect these findings, including revising residential HVAC equipment categories and refrigerant charge values to improve cost-effectiveness and greenhouse gas (GHG) savings calculations. Key recommendations include adopting new residential HVAC equipment categories (Table 3) and updating refrigerant charge values (Table 8) for both low-GWP and legacy refrigerants. The report also highlights the need for more granular data to enhance the accuracy of leakage rate estimates and cost-effectiveness analyses. These updates will benefit California’s energy efficiency programs by providing more accurate data for estimating refrigerant leakage rates and GHG emissions, aligning with the state’s decarbonization and electrification goals. The study underscores the importance of accurate refrigerant charge data in achieving regulatory compliance and optimizing energy efficiency measures. It also provides a framework for updating default assumptions and improving the reliability of tools used in energy efficiency programs.