Because of rising energy costs, of considerable interest in many parts of the world is the smart energy meter: a tool to let consumers know how much electricity they are using in their homes or offices at any given time. Instead of guessing at how much energy they are using and waiting to see their bill at the end of the month, users can directly observe the costs of, for example, leaving a computer on overnight, or how much they save by lowering the heat by one degree. The current project studies how consumers react to energy meters in their homes: how much and in what way they save energy, if these changes are lasting, and how to encourage further energy savings.