Assessment of Regional Residential Energy Performance Using Degree Days

This study proposes a climate-adjusted framework for evaluating regional residential energy performance by introducing Energy Consumption per Degree-Day (ECDD), an indicator that normalizes end-use energy consumption by climatic demand. This study belongs to the second category of research. Using microdata from Japan’s Statistical Survey on Household CO2 Emissions (SSH), we constructed a bias-reduced Household Micro-Resampled Population (HMRP) through stratified resampling that controls for climatic zone, urban scale, household size, dwelling type, and construction year, enabling consistent regional comparison. Results indicate that newer dwellings exhibit lower energy intensity. Heating and hot water ECDD show a positive nonlinear relationship with degree-days, converging under high thermal loads. In contrast, cooling-related ECDD shows a negative correlation with cooling degree-days, suggesting relatively efficient operation in warmer regions. These findings demonstrate that climate-adjusted efficiency is jointly shaped by structural characteristics and occupant behavior. The proposed ECDD–HMRP framework provides a practical and internationally relevant approach for climate-normalized residential energy assessment.