Efforts to improve energy efficiency in residential buildings through targeted interventions have yet to achieve sufficient reductions in greenhouse gas emissions to mitigate climate change effectively. A key obstacle is that current policy measures often fail to account for local variations in sociodemographic factors that influence energy performance. Although extensive research has examined general barriers to energy efficiency, there is a lack of focus on how local sociodemographic conditions impact these outcomes. This study addresses this gap by analyzing Energy Performance Certificates (EPCs) and sociodemographic data from the South Yorkshire region in England. Our findings reveal that energy efficiency is correlated with sociodemographic factors, such as deprivation, household type, and age, with these relationships varying significantly across different demographic groups. For instance, deprivation and specific household types, particularly “Other household types,” are critical determinants of lower energy efficiency, while age groups above 75 years significantly influence EPC ratings, especially in older homes. Retrofit activity was also influenced by sociodemographic factors, with household composition and educational attainment influencing retrofit adoption. These insights suggest that local policy instruments should be tailored to address the specific sociodemographic characteristics of regions like South Yorkshire. The study identifies key factors influencing energy efficiency at a regional level and demonstrates how targeted policy interventions can better support energy efficiency improvements, thereby contributing to broader sustainability goals.