This paper analyzes choices concerning the increase of energy efficiency made by the Swiss energy policy elite; it is based on interviews with 240 of its members. It starts from the assumption that choices depend on characteristics of the actors involved (their membership in policy coalitions, their core beliefs etc.), the characteristics of the instruments (in particular their familiarity and the extent to which they impose constraints upon the coalitions involved) and of the policy context (policy equilibrium vs. rapid change). Depending on these characteristics, actors are expected to make choices which are to a greater or lesser degree value-rational or instrumentally rational. The results of the present analysis indicate that, rather than being exclusive alternatives, the two types of rationality often complement each other in choices among policy instruments. We hope that they provide a promising opening in the often rather sterile debate between advocates of the rational choice approach and practitioners of more classical approaches of policy analysis.