Educational buildings such as kindergartens, schools and universities display many similar design, operation and maintenance features in most countries. The two most noteworthy similarities amongst these building types are the high energy consumption and the necessity for retrofitting many buildings within this sector. However, studies have shown that during retrofit, energy saving measures are only rarely applied, because the decision-makers lack knowledge of investments and the efficiency of potential energy saving measures. The main goal of the International Energy Agency ECBCS Annex 36 is to provide the educational building decision-makers with sufficient data, information and tools to improve their learning and teaching environments by improving the energy efficiency of their buildings. This is the background for the development of an Energy Concept Adviser (ECA) for energy and financial retrofit measures that is useful during the planning and concept development phases for educational buildings. On the one hand to help the owner to find the most efficient energy saving measures and on the other hand to prevent that exaggerated expectations are raised. The ECA should be applicable during the entire retrofitting phase to ensure that both the calculated energy savings and financial success will be achieved after retrofitting. This paper describes a tool that assists educational building decision-makers while the construction project is still in the design phase. This tool will improve new or existing buildings through the identification and calculation of potential energy savings. The ECA includes suggestions of energy systems to use and potential design concepts to be considered during the design phase. During the past 6 years, data have been gathered from all the 10 participating countries of the Annex 36. This electronic Internet-based tool incorporates an interactive source book of information, which includes design concepts, design advise, design and decision programs, and case studies. The tool has been translated into several languages. (c) 2007 Elsevier B.V. All rights reserved.