This article distinguishes between energy efficiency and the economically efficient use of energy resources. Policies intended to enhance energy efficiency are unlikely to contribute to the economically efficient use of energy and are therefore likely to waste resources. Policies that enhance the economic efficiency with which resources are used may increase or decrease energy efficiency, or leave it unaffected. The implication is that energy efficiency and economic efficiency are different policy goals, one promoting the use of fewer energy resources, the other promoting the efficient use of all resources.