In October 2023, the European Union adopted a new green energy policy, mandating a reduction in total final energy consumption to 763 Mtoe by 2030. To achieve these rigorous targets, which include the residential sector (accounting for approximately 25%), the scientific community must intensify efforts to integrate passive solar systems in energy-efficient buildings in the coming period. This paper numerically (using Google SketchUp and EnergyPlus software) investigates the novel energy-efficient building strategy that combines various traditional, bioclimatic, passive solar and green architectural solutions: earth-sheltered building, Trombe wall and horizontally placed pergolas (with seasonal tracking mechanism). The energy benefits of the presented strategy (scenario S3) are proven compared to the earth-sheltered building (scenario S2) and the above-ground building (scenario S1). All buildings are intended for the permanent residence of four-member families during the year and with the same room layout, habits and thermo-technical (space heating, space cooling, water heating, artificial lights and electric equipment) performance. Simulation results indicate that the annual electricity consumption for space heating in the earth-sheltered building with Trombe wall and pergolas (scenario S3) is 52.56% and 15.79% lower than the above-ground building (scenario S1) and the earth-sheltered building (scenario S2), respectively. Using pergolas (in front of the Trombe wall), the annual electricity consumption for space cooling in scenario S3 does not increase compared to scenario S2, while the savings compared to scenario S1 exceed 19%.