This study is part of a long-term research work concerning the development of a mechanical ventilation system with low energy demand. Through use of decentralised fans instead of flat plate dampers pressure drop over dampers can be eliminated. Consequently, the main fan does not need to be dimensioned for the total pressure drop in the entire duct system - but only for the branch with the lowest pressure drop. Hence, the energy demand is reduced. The methodical procedure for converting a conventional ventilation system with dampers into a system with decentralised fans has been explained in a previous study. The purpose of the present study was to corroborate experimentally the energy saving potential predicted theoretically. Furthermore, in order to relate to realistic size ventilation systems analyses have been undertaken based on an existing office building intended for 50 occupants. The findings are that the results of the experimental studies correspond well with the theory for the performance of a ventilation system with decentralised fans and that the expected energy savings are achievable. Analyses of the results of the calculations on the real-size office building show energy savings of about 30% when compared to a conventional ventilation system with dampers. (C) 2014 Elsevier B.V. All rights reserved.