In January 2002 the EU RESHYVENT project started, a three-year project within the EU Fifth Framework Programme on the investigation and development of demand controlled hybrid ventilation systems in residential buildings. The project is a clustering of four industrial consortia with a multi-disciplinary scientific consortium. Each of these industrial consortia will develop a working prototype of a hybrid ventilation system for a specific climate. A scientific group with 12 partners from research institutes, consultants and universities will carry out the scientific research work for the development of these systems. This paper gives a summary and update of the work carried out so far.