The actions to limit the energy consumption and the electricity demand lead in Europe and inFrance to think about the energy labelling of the consumption of the fans used in ventilationsystems. This is a complicated task as it has to take into account the multiple possibleoperating conditions, the eventual presence of a regulation system and the type of use.A study supported by Ademe has been carried out in order to propose a method for labelling ofthe ventilation units. This study was divided in four phases.