How do you change the daily habits of an entire city? Three German cities formed a coalition to answer this question, recognising that consumption-based emissions —from food choices to mobility patterns to heating decisions—require far more than technical fixes. CoLAB created a shared framework called the "House of Change", combining physical transformation spaces, digital engagement tools, and new governance structures to make climate action visible, accessible, and social. Led by Mannheim, the project tested whether cities can shift behavioural norms at scale.

The pilot involved Mannheim, Aachen and Münster.