Your HVAC system includes several components that work together to keep your home’s air quality comfortable. That said, it is easy to get confused with what these components all do. As it happens, your HVAC system has three major components: the outdoor unit, the indoor unit, and the air handler. The air handler is such an important part of an HVAC system. And yet, many of our Pasadena clients do not know much about it, let alone what it does exactly. Fortunately, our BBB-rated HVAC technicians explain all about this important appliance.

What Is an Air Handler?

Like a furnace, an air handler is a cased unit in larger HVAC systems with evaporator coils, a blower, ventilation parts, and an air filter. Its main function is to circulate air throughout your home. This appliance connects to the ductwork and provides heating or cooling, depending on its location and purpose. Most air handlers are often in the attic, basement, or a dedicated closet.

Are Air Conditioners and Air Handlers the Same?

Though some believed them to be the same, these are two separate systems working together to cool homes. The air conditioner is the outdoor unit, while the air handler is located indoors. These systems are connected by refrigerant lines, with the air handler helping to facilitate the cooling process.

Parts of an Air Handler

Air Filter

HVAC systems have an air filter within the air handler, between the fan and the intake ducting. This filter removes any contaminants from the air before it enters the system, which protects the system components


The blower fan is responsible for circulating air that an HVAC system has conditioned. It moves the air from the system into the ductwork to distribute the air throughout the home.

Evaporator Coils

One of the air handler’s main tasks is to absorb heat to begin the cooling process. This function is made possible by the evaporator coils. These coils contain low-pressure, low-temperature refrigerant gas. As air passes over them, this refrigerant absorbs excess heat from the air. 

Types of Air Handlers

Terminal Units

Also called terminal units, blower coils, or fan coil units, these smaller units typically have only an airstream, a blower, and a coil. 

Makeup Units (MAUs)

Makeup air unit (MAU) is larger than terminal units that conditions 100% of outside air and does not recirculate any airstream.

Rooftop Units (RTUs)

Finally, there is a type of AHU designed specifically for outdoor use on roofs. It is called the rooftop unit (RTU) and is mostly used in commercial settings.

Common Symptoms of a Failing Air Handler

Weaker-Than-Normal Airflow

Your blower motor may malfunction if the airflow from your vents is weaker than usual or changes strength throughout the day. Ignoring this issue can cause more strain on your air handler, eventually causing it to break down. Thus, your motor can benefit from a thorough cleaning because dirt can affect its performance.

Air Conditioner Freezing up in Summer

A dirty or clogged air filter is one common cause of your air conditioner freezing up in the summer. Another possibility is that the evaporator coils need to be cleaned. However, it could also indicate a refrigerant leak, wherein you may need to replace your air handler.

Higher Energy Bills

While it is normal for your energy bills to be higher during seasons like winter or summer, unusually high bills can indicate a problem with your HVAC system. For example, a faulty air handler or other potential problems can cause big spikes in your energy usage.

How Do You Know if You Need an Air Handler?

You may not need an air handler for a traditional gas, electricity, or oil furnace. However, depending on the type of heating system you are considering (e.g., an electric heat pump), investing in an air handler could be a wise choice. Some heat pump and air conditioner systems sold today already include one.

Heating and Air Near Me

Pioneers Heating and Air is your one-stop shop for all your air handler repair and installation needs. We have years of experience working on all makes and models of air handlers, so we can help you get your system back up and running quickly and hassle-free. Plus, our knowledgeable technicians are always available to answer any questions. So please do not hesitate to call us to ensure you get the best service for your investment.

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