The interlinked nature of today’s societal challenges asks for integrative approaches. The energy transition is an especially impactful challenge and presents a compelling opportunity to pursue integration, as it requires changes to space, landscape, infrastructure and organizations at different scales. While the added value of integrative approaches that address the energy transition alongside other societal challenges is widely acknowledged, it is not the status quo. The aim of this study is to uncover the institutional barriers to integration and suggest possibilities for redesign. The paper sheds light on a hitherto relatively understudied phase of integration, namely implementation. Two illustrative cases for energy transition integration are discussed; (i) sustainable residential heating combined with climate adaptation in the urban context, and (ii) biogas production from livestock manure for rural residential heating and nitrogen reduction in the Netherlands. Inspired by the Institutional Analysis and Development framework (IAD) and networks of action situations (NAS) concept, the study shows that in the context of energy transition integration, action situations are pillarized with incidental interactions happening between sectors and across scales. The rules that govern actor interactions stem from sectoral institutional arrangements and produce sectoral action situations. Factors that especially obstruct integration are financial streams, budgeting and designated task responsibilities of actors that favour sectoral, one-dimensional projects. Actors interact in sectoral action situations and struggle to establish links to plan for more integrative outcomes. As a way forward, the study illustrates how rules can be redesigned to create integrative action situations and what mechanisms may help to achieve this in practice.