In international climate and energy policy the development of smart grids features as a critical new step in the transition towards a sustainable energy future. Smart grids enable two-way energy and information exchange between households and energy providers. Drawing on social practice theories, transition theories and informational governance, this thesis seeks to shed light on the changes that are taking place at the level of households: How do householders understand, handle and use new information flows? How can we conceptualise the interplay between households and smart energy systems? And what does this mean for householder participation in smart energy transitions? The thesis suggests that the key to understanding and governing the social dynamics of smart grids lies in the ‘Home Energy Management-practices’ (HEM-practices) that are emerging at the interface between households and wider energy systems.