The Fan Optimiser does more than just save energy.

With today's current financial climate and in this environmentally aware, energy conscious time, any new product that can save energy usage and therefore save money is becoming increasingly attractive to the end user and designer alike.

However, when TGA Consulting chose to use the Belimo Fan Optimiser on St Martins School in Northwood it was not just to save energy. As large proportions of the new building at St Martins were to be used for music practice rooms the original concern was reducing noise.

The Belimo Fan Optimiser when used with Belimo VAV controls can reduce fan energy consumption by up to 50%. A normal VAV system runs with a duct pressure high enough to supply air to the index box in a maximum air condition, therefore in normal everyday use a great deal of the VAV boxes would be closing off against excessive pressure, in some cases only being open approximately 10%. This not only uses excess energy running the fans faster than they need to, but also creates more noise at each individual box.


Using the MP bus information the optimisers look at the damper position of each motor and turn the fan speed down until the damper position of the most open box is approximately 90% open therefore supplying just the amount of air that is actually required for the current situation. Reducing the amount of pressure that a damper has to close off against also reduces the noise levels at each individual box and therefore in each room.

At St Martins School the system also incorporates Belimo CR room controllers which also control the heating valves bringing in heated air through the VAV units eliminating the need for additional heating. The CR24-B3/A3 controllers are also linked to PIR sensors for each room which shut down the heating and air conditioning if the room becomes vacant, this saves even more energy when taking into account changing timetables and of course break times and lunch breaks.

Email: Kathy@belimo.co.uk