Whole-life-cycle benchmarks for domestic and non-domestic buildings: A method for definition and communication applied to the German building stock

Peer-reviewed paper 7-012-26

Benchmarking whole-life-cycle impacts is critical for aligning building design with sustainability targets. Current standards and studies recommend the definition of target-, average-, and limit-values, implemented through various methods and data sources. However, although several benchmarks already exist, a systematic process for their derivation is lacking. This paper adopts the method of the ISO 21678 to provide a clear roadmap for defining LCA benchmarks based on transparent calculations and data sources for 13 different domestic and non-domestic building usages. The methodology is designed to create a unified evaluation framework where a single benchmark scale is applicable to both new constructions and refurbishment projects, facilitating direct comparison. It combines existing top-down climate targets with bottom-up survey data and statistical sources to define key benchmark values. Further, it integrates an intuitive communication format, developed during an interdisciplinary and participative process with practitioners, to enhance usability and raise awareness for a large audience. The benchmark methodology is demonstrated through a case study for the German building stock. Results show that this method enables a structured and adaptable benchmarking process that can support integration into tools, certification schemes, and policy development. By clarifying how benchmarks could be defined, applied, and communicated, this contribution aims to foster the broader adoption of LCA benchmarking practices.