- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 15 Sep 2020
Fan coil unit
Air handling units (AHU, sometimes referred to as ‘air handlers’) form part of the heating, ventilating and air conditioning system (HVAC) that supplies, circulates and extracts air from buildings. Generally, they are connected to the ductwork that supplies air to and extracts air from the interior and can provide ventilation, heating, cooling, humidity control and filtration. For more information see Air handling unit.
Fan coil units (FCU) consist of only a fan and a heating or cooling element, are located within the space they are serving, and are generally not connected to ductwork. They may either just recirculate internal air, in which case a separate ventilation system is required, or may introduce s proportion of ‘fresh’ air that is mixed with the recirculated air.
Where fan coil units are supplied with chilled water and hot water from central boilers and chillers they are generally referred to as two pipe (either heating or cooling) or four pipe (both heating and cooling) units.
Where the heating and cooling is provided locally, they may be referred to as variable refrigerant volume (VRV) or variable refrigerant flow (VRF) systems. Here, refrigerant is circulated between one or more fan coil units and is connected to an external heat exchanger. These systems may be more prone to refrigerant leakage than units that are connected to hermetically-sealed central chillers.
When a fan coil unit cools air, it will generally cause condensation which must be collected and drained or pumped away.
 Related articles on Designing Buildings Wiki
- Air conditioning.
- Air handling unit.
- Building services.
- Building services engineer.
- Chilled beam.
- Chiller unit.
- Constant air volume.
- Mechanical ventilation.
- Mechanical and electrical (M&E).
- Natural ventilation.
- Thermal comfort.
- Variable air volume.
- Variable refrigerant flow.
 External references.
- CIBSE TM43 Fan Coil Units.
Featured articles and news
Brick slip soffit systems and intricate brick features.
Breaking down possible steps of pre-contract management.
ICE event includes comments from Welsh Government Minister Julie James.
How to write them and what they should include.
Designing Buildings Wiki becomes the world's first website to adopt the new knowledge standard.
Assessing the most beneficial design elements.
Exploring different types of vinyl flooring.
New Government task force will build beauty into reformed planning process.
Five outstanding aspects of the profession.
The seismic strengthening of historic churches.
Results show guarded optimism and payment concerns.
Noteworthy navigable aqueducts.