What Is An Air Handler?

Aug 21, 2023

The world of commercial HVAC systems has a language all its own. Of course, you only need to learn all the specialized lingo if you're an HVAC professional.


But a few terms that pop up frequently, such as air handlers and fan coil units. Read on to learn the definition and differences of a fan coil vs air handler.


What's an Air Handler?


An air handling unit is part of an HVAC system. Also known as an AHU, this component brings fresh air in from the outside. The AHU then cools or heats the air and circulates it through the building's duct system.


Air handlers use various components, such as heating and cooling coils, blowers, and sound attenuators. Some use refrigerant, while others use water to cool the air. But they all work by bringing in outside air, mixing it with indoor air, and chilling or heating the air by passing over a coil. Then the air is filtered and distributed.


What's a Fan Coil Unit?


A fan coil unit, or FCU, is a standalone system. It's not attached to duct work. Rather, it simply cools (or heats) air that's already indoors, then recirculates it.


FCUs work by drawing air over a cooling or heating coil. Then the air is recirculated. Fan coil units are often used to cool or heat smaller areas, such as single rooms.


While both AHUs and FCUs cool or heat air by drawing it across coils, they are not the same. Fan coil vs air handler differences include:

  • Air handler units are connected to duct work, and draw in air from the outside. Fan coil units use air that's already indoors, and are not connected to ducts.


  • AHUs can heat or cool entire buildings. FCUs are used to heat or cool smaller areas, such as single rooms.


  • AHUs are part of a larger HVAC system. FCUs are stand-alone units.


  • AHUs tend to be quieter and more expensive. FCUs are louder, but less expensive.


Fan Coil Unit, used to showcase the difference between fan coil units and air handlers

How Many Types are There?


When it comes to fan coil vs air handler, there are multiple types from which to choose. Let's start with fan coil units.


Two main types of FCUs have to do with how they handle air. The draw-through FCU pulls air through. The blow-through FCU pushes air. FCUs can be configured to mount on the ceiling, or the floor.


There are also two types of ACUs. Draw-through ACUs utilize fans to pull air from outdoors and draw it through a mixing box, across coils, and through filters. They may be vertical or horizontal.


Blow-through air handlers also use fans, but they push air through the mixing box, across the coils and through filters. Then the air is blown through the ducts.


How Do I Select the Right One?


Choosing the right HVAC unit for your commercial building can seem challenging. In many cases, an AHU is the best choice to heat or cool an entire building. These units work in tandem with the HVAC system and ducts.


For smaller spaces or tight budgets, fan coil units may offer a solution. These simple devices may be used to cover areas where the HVAC doesn't quite reach.


1 Source Mechanical Is Here to Help!

When it's time to replace or repair your HVAC system, 1 Source Mechanical is here to help. Our professional team will use their expertise to help you choose the right heating and cooling systems for your commercial space. Contact 1 Source Mechanical today.

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