The project IDEA – Interactive Database for Energy‐efficient Architecture – is a multinational collaborative project to build a European knowledge base on advanced energy conscious building design. At the core of this project are two earlier multimedia developments, the Swiss program DIAS and the German adaptation NESA which present the principles and applications of solar architecture in the respective national contexts. IDEA aims to improve know‐how of European professionals and exchange of information between them. The database includes information on exemplary buildings, their technical concepts and on other specific conditions. IDEA presents the existing state of the art in the field of energy‐efficient architecture by means of a multimedia database of built examples, an encyclopedia of design concepts and a set of interactive design support tools. The built examples have been selected from around Europe. IDEA assembles technical information on materials and energy‐related standards and regulations and provides climatic data from all relevant European regions.