Increased focus in research on the environmental consequences of behaviour and product usage the last decade has resulted in a number of different design strategies. The strategies are meant to stimulate desired behavioural patterns or to avoid undesired ones. Although this provides understanding of how behaviour may be changed, there has been limited discussion about when and in which context to apply the different strategies. This paper aims to investigate when different strategies are likely to have the intended effect, depending on how they divide the control between the user and the product. Factors affecting behaviour, identified by social psychology, are used as a framework for this investigation. The result is a number of guidelines that are meant to help designers make informed decisions about which behaviour changing strategies to apply.