Rising demand temperatures are widely blamed for UK home energy use not declining over time despite the increased efficiency of dwelling envelopes and heating technologies The hypothesis that thermostat settings have risen over time is tested using a repeated cross-sectional social survey of owners of centrally heated English houses No statistical evidence for changes in reported thermostat settings between 1984 and 2007 is foundWhy then has home energy use not declined over time despite homes apparently becoming more efficient? There is evidence that the energy efficiency of homes has not improved as much as previously assumed Improvements in dwelling energy efficiency and increased penetration of central heating would have increased internal temperatures without occupants demanding higher temperatures Dwelling area heated or duration of heating or window opening during the heating season may have increased over time increasing temperatures or energy use.