Buildings are the dominant energy consumers in modem cities but their consumption can be largely cut back through improving efficiency, which is an effective means to lessen greenhouse gas emissions and slow down depletion of non-renewable energy resources. However, the potential energy cost saving alone is hardly a sufficient incentive to investing into improvement measures, unless the cost of using energy soars. People's attitude will change with increasing concerns about the environment and sustainable development but the results remain insignificant. Surely, more effective means are needed to induce or compel greater efforts, especially to the signatories to the Kyoto Protocol. Whilst regulatory control is widely used, many believe that encouraging voluntary commitments is more cost effective in dealing with environmental problems. More researchers now favor the adoption of a well-articulated policy mix involving both regulatory and voluntary instruments. The paper describes a comprehensive literature review about regulatory and voluntary policy instruments related to building energy efficiency. Particular attention is given to the cost-effectiveness of these instruments, as reflected by the implementation experience of several countries, and a qualitative evaluation. The possibility and benefits of harmonizing governmental and private-sector schemes are discussed. (C) 2004 Elsevier Ltd. All rights reserved.