Establishing the cost of housing: evolution and effects of Germany’s KdUH housing benefit scheme

Housing benefits are a crucial tool in shaping housing affordability and access within welfare states. By analyzing Germany’s largest housing benefit scheme, Kosten der Unterkunft und Heizung (KdUH), we find that housing policy instruments can subvert their stated goals due to their instrumentation. Drawing on legal texts, court rulings, administrative guidelines, and a case study of Wuppertal, the article explores how legal, fiscal, environmental, and spatial objectives are embedded in the scheme’s technical design. Applying a policy instrumentation lens, it traces the evolution of the legal concept of ‘reasonableness’ and the rise of standards like the ‘coherent concept’. The case study shows how seemingly minor technical definitions—such as which components of rent are included—substantially impact housing availability, quality, energy performance, and public costs. The findings highlight how decentralized, data-driven implementation can depoliticize welfare policy while producing complex and unintended ecological and social outcomes.