The project, funded through the sixth Energy Research Programme under the theme “Research for an environmentally friendly, reliable and affordable energy supply,” began in 2018 with the aim of developing methods, data and tools to minimise the energy demand and greenhouse‑gas emissions of buildings throughout their life cycle. The work was carried out in close cooperation with national institutions such as the Fraunhofer Institute for Building Physics (IBP), the German Building Research Institute (BBSR), the energy agency dena and the German Institute for Standardisation (DIN). The project leader also served as chair of the DIN committee on sustainable building, ensuring that the research was directly linked to the development of national and European standards. International collaboration was anchored in the International Energy Agency’s Energy in Buildings and Communities (IEBC) programme, specifically the Annex 72 work package, and the project contributed to the ongoing work of ISO Technical Committee 59 Subcommittee 17 and the European Committee for Standardisation (CEN) Technical Committee 350.

The scientific output of the project centred on the systematic capture, assessment and targeted influence of the energy consumption of building construction, operation and maintenance. Building on the long‑standing German tradition of life‑cycle assessment (LCA) that dates back to the 1920s, the project refined the calculation rules for primary energy consumption (non‑renewable) and the associated greenhouse‑gas emissions, which are now recognised as core indicators in sustainability rating systems such as BNB and DGNB. A key deliverable was the public database “ökobau.dat” (available at nachhaltigesbauen.de), which aggregates LCA data for building products and construction elements, thereby providing planners and designers with ready‑made, evidence‑based inputs for their projects. The project also produced a set of guidelines and a planning aid that integrate building information modelling (BIM) with life‑cycle energy assessment, enabling architects and engineers to evaluate the environmental impact of design choices early in the project cycle.

During the project’s execution, the team produced a series of interim reports that informed national policy discussions and contributed to the German positions in the international standardisation processes. The work also addressed the question of whether buildings with near‑zero energy balances in the use phase could lead to higher overall life‑cycle energy demand due to construction and maintenance. The findings confirmed that a balanced approach, which considers both construction‑phase and use‑phase energy, is essential for genuine sustainability. The project’s results were incorporated into the final reports for Annex 72, which were completed in late 2023 after a project extension prompted by the COVID‑19 pandemic and the resulting delays in international partner contributions.

Financially, the grant covered a dedicated staff position, travel expenses for participation in national and international meetings, third‑party costs for commissioned life‑cycle analyses, and other operational expenses. The project’s timeline extended from its initial start in 2018 to the completion of the final reports in 2023, reflecting the extended duration required to meet the IEA’s deliverables. The collaboration with Fraunhofer IBP, BBSR, dena, DIN and international partners ensured that the technical results were not only scientifically robust but also directly applicable to the planning and regulatory frameworks in Germany and beyond. The project’s outcomes are now available to practitioners, policymakers and researchers, providing a solid foundation for the continued development of energy‑efficient and low‑emission buildings across Europe.