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What Does The Air Handler Do For My HVAC System?

November 5, 2015

The air handler is a vital section of any HVAC system. It is responsible for managing the air that comes into the heating or cooling system and distributing this throughout the premises. Size can vary as there are large ones that are connected to ductwork and small ones that interact directly with the local space. There are multiple parts that make up these air handling units or AHUs. Each of them performs a specific task to help achieve optimum comfort. Let’s look at some of them below:


Before circulating air, the AHU must ensure that it is clean enough not to cause harm to people. That’s why it contains a filter to catch most of the impurities floating around from dust to pollen. If inhaled, these could trigger allergies and other respiratory issues. It might lower productivity and increase absences in workplaces to the detriment of the business. This filter will get filled with dirt after a few months resulting in a decrease in effectiveness. Hence, it should be replaced regularly as part of maintenance work.

Heating or Cooling Elements

Inside these AHUs are heating elements for heat pumps and cooling elements for air conditioners. For A/Cs, these are typically evaporative coils facing the room which absorb the heat from the surrounding air. These coils are so cold that they are able to condense some of the vapor in the air which in turn lowers the humidity. This has the side effect of making the room feel cooler without changing the temperature setting of the thermostat. The water droplets make their way down into a pan which drains outside.

Blower or Fan

The cold air around the evaporator coils is then blown to the room, in the case of small split type air conditioners, or to the ductwork, in the case of larger centralized systems. The speed of the blower can be adjusted automatically or manually for best results depending on the conditions. Sometimes there are multiple fans to help things along in a massive duct network. One set will be supply fans while the others will be return fans.

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About The Author

Brody Pennell

Since 1945, Brody Pennell Heating & Air Conditioning is the committed to helping homeowners in the greater Los Angeles area experience total home comfort. In 2021, the readers of the Los Angeles Times voted Brody Pennell the Best HVAC Company in the area.

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