Low-carbon retrofit of owner-occupied housing will make a significant contribution to reducing UK CO2 emissions. However, despite placing the home within its social context, there remain concerns that existing practice theory studies on this topic fail to adequately conceptualise ‘large’ phenomena such as retrofit. In response to this gap, this research adopts a novel nexus-of-practice approach to understanding home improvements. Drawing on thirty-one in-depth interviews and walk-through tours with owner-occupiers in Bristol, a rigorous line-by-line coding and analysis of the relationships between components of practice is undertaken. Particular attention is given to: connections between home improvement practices and the wider nexus of practices; how these connections can increase adoption of low-carbon retrofit measures; and the implications of these for the role of the architect. The findings reveal indirect relationships between low-carbon retrofit measures and other home improvement practices. They also illustrate that professional competences associated with low-carbon retrofit measures are poorly connected to the wider nexus. These connections have implications for policy seeking to encourage higher levels of low-carbon retrofit, and contribute to architects’ ability to recognise and seize opportunities to maximise the environmental benefits of owner-occupier home improvement projects.