AHU and FCU are abbreviations used to describe two different multiple HVAC systems. However, these heating, ventilating, and air conditioning system use the same cooling coil system.
The AHU, which is completely known as the air handling unit is very different from the FCU or the fan coil unit in this way.
The air handling unit (AHU) is a used in the HVAC system. It will cool and distribute air into your living space through the use of a duct.
The fan coil unit (FCU), on the other hand, is a standalone system. It is used to circulate the “existing air” in any small space. However, it can also form part of the HVAC system.