The smart metering systems currently being installed in UK households support devices that give feedback aimed at encouraging behaviour changes, specifically to reduce energy demand and spending on energy. Detailed standards specify the minimum technical capabilities of the smart meters and feedback devices. In this paper, we assess the extent to which these standards enable feedback that is likely to be effective in reducing demand. Latest research in this field, drawing on theories of social practice, suggests that feedback devices assume and rely on what we term 'reflection practice', a distinctive type of social practice, and that feedback attentive to the particular energy-using practices of householders is likely to have most influence on demand. Neither the smart meter standards nor current commercial devices are found to incorporate these latest research findings, potentially significantly limiting the ability of the UK smart metering programme to fulfil its domestic energy demand reduction objectives.