Combining insights from research on systems innovation and sustainable transitions with multi-level governance perspectives, this paper examines the ‘Arbed’ domestic housing retrofit programmes in Wales. In so doing, the paper demonstrates the critical role of sub-national government in the emergence of a distinctive sustainability-oriented pathway for domestic end-use energy demand reduction in Wales, and highlights the multi-level governance challenges involved. The governance processes contributing to this purposive transformation (e.g., policies and institutions; a ‘shared’ normative vision; network building; competencies, resource mobilisation, etc.) are illuminated and how they simultaneously cut across multiple spatial scales is discussed. Rather than simply viewing such transition arenas as simple sites of experimentation, the paper argues that sub-national sustainable energy transitions and pathways are shaped by pressures and opportunities that are mediated by unique place and context-specific conditions that exert influence on the mobilisation of resources, governance capabilities and actor-networks.