A longitudinal study was conducted to assess the effects of several intervention techniques on energy conserving behavior in an organizational setting (N = 150). During the first phase the effects of three-weekly feedback, weekly feedback and no feedback were compared through self-report questionnaires. In the weekly feedback-condition electronic data collection about energy consumption was used for feedback; in the three weekly-feedback condition self-report data were used. In the second phase, after a withdrawal period of 4 months, commitment and information were added as intervention techniques. Results will be discussed during the presentation.