A transition to zero carbon buildings is needed for mitigating climate change. Yet, it is far from gaining sufficient momentum in many countries, particularly the United Kingdom. This article focuses on actors and platforms facilitating change towards zero carbon residential buildings by integrating the concepts of innovation intermediaries and champions. Drawing on interview data and building on the literatures of innovation intermediaries, champions and Strategic Niche Management, the article analyses actor configurations in three new build housing projects. The findings show that actors and platforms acting as innovation intermediaries advance zero carbon buildings at different stages of project development, with varying intensity, influence and longevity. Some intermediaries take also championing roles, while also other actors champion projects when intermediation is absent. At a time of limited policy support for zero carbon housing innovations, intermediation and championing activities become especially important in the transition towards zero carbon buildings.