This paper examines the participation of Dutch households in a smart and sustainable energy transition. Particular attention is paid to new forms of cooperation that are arising between households (horizontal opening-up) and between households and service providers (vertical opening-up). Data are drawn from an online survey and a focus group discussion among householders who have some experience with sustainable energy practices. To guide the analysis we discern three energy management practices that come along with the advent of smart energy systems (energy monitoring, renewable energy production and time-shifting), and three social arrangements entailing different ways of organising these practices (private, horizontal and vertical arrangements). While survey respondents, in general, prove to be supportive of both vertically and horizontally arranged energy management practices, we also find that they run into specific privacy and autonomy problems that shape or even impede their participation. In addition, the focus group shows that shared understandings of conventional energy systems and shared experiences with alternative schemes create strong parallels between anticipated arrangements of new practices. It is concluded that decentralised systems are particularly promising for promoting householder participation, as they enable the bundling of energy management practices and the renegotiation of horizontal–vertical relationships.