Households constitute an important target group for energy conservation. They not only use energy in a direct way (gas, electricity and fuel) but also in an indirect way (embedded in the production, consumption and disposal of goods). During a period of five months (viz., October 2002-March 2003), direct and indirect energy use and direct and indirect energy savings of 189 Dutch households were monitored. The study examined the relative importance of socio-demographic variables and psychological variables in relation to household energy use and changes in energy use (viz., energy savings). For this purpose, variables from the theory of planned behavior [Ajzen, 1. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50, 179-211] and the norm activation model [Schwartz, S. H. (1977). Normative influences on altruism. in L. Berkowitz (Ed.). Advances in experimental social psychology (Vol. 10, pp. 221-279). New York: Academic Press] were used. Results indicate that energy use is determined by socio-demographic variables, whereas changes in energy use, which may require some form of (cognitive) effort, appear to be related to psychological variables. The variables from the norm activation model were able to significantly add to the explanation of energy savings, over and above the variables from the theory of planned behavior. Also, different types of energy use and energy savings appeared to be related to different sets of determinants. (C) 2009 Elsevier B.V. All rights reserved.