The IEA ECBCS Annex 36 deals with the energy retrofit of educational buildings. Researchers from 10 participating countries from Europe and the US are collecting information on retrofit measures and case studies and are developing an energy concept adviser for technical retrofit measures. This internet-based computer tool for decision-makers is the main outcome of the annex. One of the most important inputs to the tool is the collection and assessment of case studies, which is also presented in a specific report. 25 case studies from Denmark, Finland, France, Germany, Greece, Italy, Norway, Poland, UK and the US are included into the collection. For each case study the report consists of a description of the state before the retrofit (geometry, construction and HVAC-system), the used retrofit measures, the resulted energy savings, the renovation costs and the experiences or lessons learned during the retrofit and the user feedback afterwards. The buildings are divided into different building types. A summary including a matrix on the used retrofit technologies per building and an overview on the reached energy savings are given. The paper for the AIVC BETEC 2003 gives an overview on all buildings and specifies on the used technologies with focus on energy and ventilation.