This paper outlines the Europrosper project whose objectives are to :1. Consolidate and where appropriate harmonise methodologies for energy certification of existing office buildings across 6 European countries whilst allowing customisation in each country to accomodate existing techniques and national contexts2. Develop training courses to instruct practitioners on how to use the certification methods, to include self-certification procedures3. Conduct a demonstration phase and4. Define the role and activities of a national centre in each country which would manage a building energy certification programme to include issuing certificates, maintenance of benchmarks and accreditation of assessors. The project will pave the way for permanent facilities to be established in the participating countries, with the potential to oversee the implementation of the certification aspects of the EU Directive on the Energy Performance of Buildings. It will also prepare the ground for the extension of the methods and training procedures into the other nine EU countries.