Scaling up retrofit: regional challenges and opportunities for MMC

Increasing energy retrofit rates is considered essential for reducing housing-related greenhouse gas emissions, particularly in Central and Northern Europe. In Germany, despite ambitious and costly policies, annual retrofit rates have remained largely stagnant at around 1% of the housing stock. The current trend of modern methods of construction (MMC) and digitisation have renewed hope that serial retrofit and service platforms could enable the scaling up of energy retrofits by reducing costs, disruptions and management burdens, especially for non-professional property owners. While a growing literature explores this potential, empirical research on the region-specific conditions to scale up serial retrofit remains limited. To address this gap, this study interviewed intermediaries and professionals who organise retrofits in the Freiburg region in south-west Germany. Their views were sought on the challenges and opportunities for serial (prefabricated) retrofit facilitated by digitised planning, platform thinking, and collaboration among trades and other partners. Applying the challenge-oriented regional innovation systems (CORIS) framework revealed an early-stage reorientation pathway in the region, providing entry points for scaling up MMC. PRACTICE RELEVANCE There is leeway for practitioners to deepen existing and create new networks across sectors and trades, and to experiment with collaborative methods, working towards serial approaches. The early adoption of innovative methods and the use of regional and renewable resources is recommended to strengthen both ecological sustainability and the regional economy. As for governance, the provision of digital tools and legal bases for data collection is essential to promote a transformation pathway for MMC and platforms. Institutional innovations such as publicly funded one-stop shops and database can contribute to a comprehensive housing transition.