Specific fan power - a tool for better performance of air handling systems

The electrical energy needed for ventilation fans and air handling units (AHU) plays an increasing role in the energy demand for buildings. Recent studies show that the electrical energy consumption can rather easily be reduced from the "traditional" level (between 5 and 10 kW/m3s) into a modern level (2 to 2,5 kW/m3s) with proper design and installation. Even lower levels are technically possible, but not yet widely economically feasible. Several countries have already set, either as requirements or as recommendations, maximum target values for SFP. This has been the first important step towards energy efficient air handling systems. However, in real practice other measures are needed, including simple but reliable tools for designers for SFP calculation, and measuring guidance for installers. To check and assess the SFP should be easy and clear also for the building owner, the end user, the inspectors etc. The need for measurements should be taken into account in the AHU construction to enable easy but reliable measuring, and guidance is needed for system design as well as for those who perform the measurements.