This project is funded by the Carnegie Trust and aims to explore changing patterns of house size, space per person and expectation of privacy in the home. Domestic energy research and policy is critiqued by social scientists for being dominated by techno-economic thinking, which overlooks critical social considerations that also impact on energy demand. Despite increasing contributions by sociologists, historians, and geographers to provide more complex and contextual accounts to inform intervention strategies (e.g. challenging the normalisation of thermal comfort as 21C, which local and cultural ways of coping with variation in indoor temperatures) changes in house and household sizes are missing from these debates. Decreasing household sizes and rising space per person significantly influence energy demand per capita, and are widely seen to undermine energy savings from improved energy efficiency. This project will be a first step in a broader programme of work expanding our understanding of changing patterns in space per person, allowing the development of novel strategies for reducing energy demand.