Energy-saving improvements in the thermal properties of buildings often have an adverse effect on indoor air quality, leading to risks of structural deterioration. In these cases, the air change rate inside dwellings must be increased while ensuring that flued gas appliances continue to function correctly. The proposed ventilation system is a cross between natural draught and controlled mechanical ventilation. It activates natural ventilation of the dwelling by means of the induction principle. To develop this system a feasibility study was performed, financed in part by the JOULE III programme - CRAFT procedure (exploratory phase). This study enabled us to validate the technical principle applied, to identify the potential market and to set up a European partnership.