Smart Readiness in European Residential Buildings and the Role of Building Condition in the SRI–EPC Association

Residential buildings pose a specific challenge for smart-readiness assessment because limited automation and heterogeneous renovation histories may decouple digital functionality from conventional energy ratings. This study analyzes 87 Smart Readiness Indicator (SRI) assessments from 16 European countries to characterize smart-readiness levels and examine their association with geographical context, residential typology, building condition, Energy Performance Certificate (EPC) class, and total primary energy consumption. The overall SRI was low (18% on average). Geographical macro-area and residential typology were not significantly associated with SRI, whereas building condition showed a strong association (p < 0.001; ε2 = 0.56), with median SRI values of 10%, 37%, and 26% for existing, new, and renovated buildings, respectively. SRI was negatively associated with EPC class in bivariate analysis (r = −0.55, p < 0.001, N = 38). In the source-concentrated 32-building complete-case subset, adjusting for building condition reduced the EPC coefficient by 54%, although the uncertainty around this reduction was substantial. The association with total primary energy consumption was uncertain (N = 10). Overall, EPC class and building condition were closely intertwined, and their independent contributions to SRI could not be clearly separated. Energy performance and smart readiness should therefore be treated as complementary but distinct dimensions.