This study develops a Future Building Energy Atlas (FBEA) for Sofia, Bulgaria, integrating land-use change modelling and spatial energy-demand assessment within a GIS framework. Future land-use patterns toward 2074 are simulated using a hybrid Artificial Neural Network–Cellular Automata (CA-ANN) model, while building energy consumption is estimated using cadastral data, gross floor area calculations, and energy coefficients derived from more than 2,500 certified buildings across ten functional categories under the medium-energy consumption. Future energy demand is projected based on historical trends observed between 2000 and 2020, during which building energy consumption increased steadily. The results indicate continued urban expansion primarily at the expense of cropland and forest areas. Cropland is projected to decline from 36.4 km² to 26.5 km², while forest areas are projected to decrease from 16.7 km² to 14.4 km² by 2074. At the same time, building energy demand increases significantly. The daily mean maximum energy consumption is projected to increase from 35.2 W/m² in 2024 to approximately 115 W/m² by 2074. These results highlight the strong relationship between urban growth, land-use transformation, and increasing energy demand in the building sector.