Abstract There is a large untapped potential for improved energy efficiency in various sectors of the economy. Governmental industrial energy audit programs subsidizing the companies to conduct an energy audit are the most common policy in trying to overcome the energy efficiency gap. Evaluation studies have been carried out to gain knowledge about the success of a completed energy audit policy program. The evaluations were made in different ways and in addition focused on different performance indicators and used different ways of categorizing data. In this article, a literature review has been made of five evaluation studies from different energy audit programs, where the problems of the present incomparability between programs due to differences are discussed. The policy implication of this paper is that new energy audit policy programs must distinguish a harmonized way of categorizing data, both regarding energy efficiency measures and energy end-use. Further, a proposition for a standard for how to evaluate energy audit policy programs is suggested. Conclusions from this study are that important elements, such as the free-rider effect and harmonized energy end-use data, should be defined and included in evaluation studies. A harmonized standard for evaluating audit programs is not least needed within the EU, where member states are obliged to launch audit programs for large enterprises, and preferably also for small and medium-sized enterprises. This paper serves as an important contribution for the development of such a standard in further research.