Rising energy procurement costs and declining capital costs for renewable technologies are provoking interest in self-sufficiency for individual buildings. In this study, we evaluate the potential of self-sufficient energy supply for 41 million freestanding single-family buildings under current and future (2050) conditions. We identify 4,000 representative buildings, calculate weather-robust cost-minimal energy systems, and transfer the optimization results to the entire European building stock. Our analyses show that buildings in regions with low seasonality and high electricity procurement costs have a high potential for self-sufficiency. Under current techno-economic conditions, 53% of the 41 million buildings are technically able to supply themselves independently from external infrastructures by only using local rooftop solar irradiation, and this proportion could increase to 75% by 2050. By paying a premium of up to 50% compared with grid-dependent systems with electrified heat supplies, building owners could make over two million buildings fully energy self-sufficient by 2050.