The discrepancy between calculated heat demand and measured heat consumption – the performance gap – suggests that the energy efficiency of houses affects the energy-consuming habits of its occupants. This coincides with the theories of practice describing how materiality affects practices through reconfiguring practical understandings, e.g. comfort expectations. Heat-related habits are investigated in the paper across material contexts, e.g. building characteristics and technologies. Evidence based on a combined questionnaire survey and administrative data on occupants (n = 1216) living in single-family detached houses in Denmark shows that the practices of adjusting thermostats and the amount of clothing worn indoors as well as perceived indoor temperature correlate with building characteristics, e.g. energy efficiency of the building envelope and technical installations. These correlations are moderated by the socio-demographic characteristics of occupants. However, building characteristics are found to be less influential on the frequency of opening windows. The results indicate that occupants dress warmer and keep lower temperatures in energy-inefficient houses. This suggests that material arrangements have a significant influence on occupant expectations and practices, which lead to increased indoor temperatures and energy demand. A challenge for building regulations will be to account for how energy efficient house characteristics and technologies adversely affect occupants’ energy-consuming behaviour.