‘Energy sufficiency’ involves reducing consumption of energy services in order to minimise the associated environmental impacts. This may either be through individual actions, such as reducing car travel, or through reducing working time, income and aggregate consumption (‘downshifting’). However, the environmental benefits of both strategies may be less than anticipated. First, people may save money that they can spend on other goods and services that require energy to provide (rebounds). Second, people may feel they have ‘done her bit’ for the environment and can spend time and money on more energy-intensive goods and activities (spill-overs). Third, people may save time that they can spend on other activities that require energy to participate in (time-use rebounds). This presentation will review the current state of knowledge on rebounds and spill-overs from sufficiency actions, and on time-use rebounds from downshifting. I will argue that: first, rebound effects can erode a significant proportion of the anticipated energy and emission savings from sufficiency actions; second, that such actions appear to have a very limited influence on aggregate energy use and emissions; and third, that downshifting should reduce energy use and emissions, but by proportionately less than the reduction in working hours and income.