An important share of developed countries’ energy consumption is used for heating. In the past decades, increasing living space has been one of the main drivers for energy demand in the housing sector. Based on a social innovation framework and drawing on two case studies from Germany and Switzerland, this paper explores options to reduce living space in the residential sector. Both cases focus on senior owners of single family houses (SFH), an important target group, as they remain in large family dwellings after their children have moved out. In the paper, we present the results of empirical work conducted in both projects, exploring how living in large dwellings is perceived by SFH-owners and which alternative options seem feasible and promising. These insights are linked to an intervention perspective, drawing on targeted workshops for homeowners in Switzerland. The findings show that options such as densification, letting out or moving to a smaller apartment, can be appealing to senior SFH-owners, if they are linked to attractive and positive visions about living in old age. Drawing on these empirical insights, we discuss how senior SFH-owners can be made aware of the advantages of managing with less space, and how they can be motivated and enabled to do so. Based on the social innovation approach and the findings from the surveys, we add suggestions on a broader supportive policy framework.