Why specify a chilled fan coil system against a refrigerant alternative

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Why select a chilled water fan coil system over a refrigerant based system?

When considering a chilled water fan coil solution or a refrigerant-based system, there are some key factors which will ultimately impact your final specification choice. These include constraints around the use of refrigerants in buildings, safety, sustainability and building size.

Building limitations

Within new developments, there can be a limitation on how much refrigerant a building can contain. In these situations, chilled water fan coils are a more feasible specification option. They are able to deliver a comfortable environment through the use of a water-based system.


F-Gas regulations require either frequent inspection of pipework joints or a leakage detection system, both of which can be a bit costly. In comparison, chilled water systems use an inert liquid which removes the need for these additional requirements.


Refrigerants have a high global warming potential (GWP). As we push for more sustainable buildings within the built environment, specifying systems that have a reduced GWP are becoming increasingly important. Chilled water systems only require refrigerant in the main plant and therefore use much smaller quantities.

Building size

Refrigerant based systems need a plant room once they meet their maximum distance for a single pipe run. Medium to large systems may require more than one condenser which can mean additional internal and roof space is needed. A hydronic system, however, can operate from one centrally piped chiller unit installed on the roof, which can an important factor where space is a very valuable and maximising each square metre is essential.

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Chilled water fan coil systems

A chilled water fan coil system connects to a centrally located hydronic chiller and heat pump or boiler – often located on the roof to increase the amount of usable internal space. This type of system requires a two-pipe model for heating or cooling only, or a four-pipe model if heating and cooling is needed.  This means you can have a smaller riser space and fewer, if slightly larger, pipes.

As providing an optimum indoor climate for occupants becomes a wider topic within the construction industry, cooling is increasing in demand. When choosing a system, it is increasingly important to specify solutions which are futureproof, carry reduced risks and support the push for more sustainable developments.

Ability Projects offer a range of chilled water fan coil solutions for all projects types. To discuss these or a specific project in more detail, please contact our team of industry experts. We also offer a range of CPDs on the specification and design of fan coils.

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