When it comes to heating and cooling systems, many homeowners are familiar with furnaces, air conditioners, and thermostats. But an air handler often causes confusion. An air handler is a vital component in some heating and cooling systems, though not all systems require one. It’s common for people to mistakenly think of an air handler as the same as a furnace, but while there are some similarities between the two, they are not interchangeable. 

Air handlers and furnaces share certain parts and functions, but the main difference is that furnaces are specifically used for heating. If you have a furnace, you won’t need an air handler because the furnace takes care of the air handler functions. However, if you’re using a heat pump or a central air conditioner that isn’t paired with a furnace, then an air handler is necessary to complete the system.

What Is an Air Handler?

An air handler is a crucial component of your HVAC system, working alongside the heating system and cooling system to keep your home comfortable. It connects to the supply ducts and return ducts, allowing it to circulate air through the ductwork. By working with devices like a heat pump or air conditioner, it helps maintain the right thermostat setting. 

Typically, an air handler resembles a rectangular, metal cabinet, similar to the size and shape of a furnace, and is commonly placed indoors in spaces like the attic, basement, or a utility closet. This unit interfaces seamlessly with the rest of your HVAC setup, ensuring smooth air circulation and climate control in your home.

How Does an Air Handler Work?

An air handler is a key part of your home’s heating and cooling system, working closely with heat pumps and air conditioner condensers. It has many components similar to those found in furnaces, all designed to circulate and condition the indoor air. 

The fan and filter help ensure clean air flows through the system, while the cooling system’s evaporator coil cools the air or the heating coil warms it. The process starts when the air enters through the central return duct. 

Sometimes, compartments inside the air handler mix indoor air with fresh outdoor air before it passes through the filter to remove contaminants. Once purified, the air moves through the air handler’s components, either getting cooled or warmed depending on the system’s needs. 

Finally, the blower motor and fan push the conditioned air into the supply duct, where it gets distributed throughout the house, ensuring comfort. This air can either be cooled, warmed, or simply moved efficiently, depending on the settings of your system.

Key Components of an Air Handler

Let’s dive into the parts of an air handler to understand how it works.

1. Evaporator Coil

The evaporator coil is an important component found in your air conditioner. It’s connected to the outdoor condenser through refrigerant lines. When the thermostat signals for cooling, refrigerant travels through the coil, absorbing heat and humidity from the air passing over it. This process helps to cool and dehumidify the air before it’s circulated through your home.

2. Blower Motor

The blower motor is responsible for powering a fan that pushes the conditioned air from the air handler into your home’s ductwork. The air is then distributed throughout the house, ensuring comfort in every room. These motors come in different speeds to adjust how air is moved:

• Single-speed motors operate at one fixed speed, always running at maximum power, which can be less energy-efficient.
• Dual-speed motors, on the other hand, offer two speeds, usually operating at 60% capacity most of the time for better energy efficiency. They can shift into 100% capacity when higher airflow is needed.
• Variable-speed motors (often electronically commutated motors or ECM) are the most energy-efficient. They adjust the speed continuously to match the demand, keeping energy consumption low. With continuous operation, they consume much less electricity than single-speed motors, providing excellent long-term savings.

3. Heat Exchanger Coil (Optional)

The heat exchanger coil (or electric heat kit) is an optional component that can be added to an air handler. This coil contains an electric heating element that provides supplemental heat to the air. This is especially helpful in colder months when extra warmth is needed. The air blowing over the heat exchanger adds heat to the air, improving comfort in your home.

4. Air Filter

The air filter is one of the most important elements in maintaining good air quality. It cleans the air before it enters the air handler, trapping contaminants like dust, hair, and debris. Not only does it protect the components of the air handler, but it also helps improve your home’s air quality. The MERV rating of the filter shows how effectively it traps even microscopic contaminants, ensuring that you breathe clean air.

Types of Air Handlers

Air handlers can be categorized into several types based on how they’re installed and where they’re placed. The main options are multi-positional, wall-mounted, and ceiling-mounted air handlers. Each of these types is designed for different needs and installation environments, allowing for flexibility in both designs and configurations.

Multi-Positional Air Handlers

The multi-positional air handler is perhaps the most versatile of all. As the name suggests, this type can be installed in various positions depending on the space and needs of the building. It’s a conventional system that can be used in homes and commercial spaces. You can install it vertically for upflow or downflow airflow, or horizontally for right-flow or left-flow—perfect for different building layouts and ventilation requirements.

This flexibility makes the multi-positional air handler ideal for different setups. Whether you need a system that pushes air upward, downward, or sideways, this unit has you covered.

Wall-Mounted Air Handlers

If you’re dealing with tight spaces and need a solution that doesn’t take up much room, a wall-mounted air handler is an excellent choice. These units are mounted directly on the wall studs and are typically shorter and wider than other types of air handlers. They fit well in areas like utility closets, where there might not be a lot of space for larger systems. The wall-mounted air handler is perfect for small spaces in homes, offices, or apartments.

Ceiling-Mounted Air Handlers

For areas where limited space is a concern, ceiling-mounted air handlers are a great solution. These units are installed above the ceiling, making them an ideal choice for homes without ductwork. They’re significantly smaller than wall-mounted air handlers, so they can be used in spaces where other systems would be too bulky or intrusive. Whether you’re looking to optimize space or keep the unit hidden from view, a ceiling-mounted air handler does the job.

Air Handler vs Furnace

Air handlers and furnaces share some common components, but a furnace has the necessary elements like burners and heat exchangers to generate heat, which air handlers lack. Homes with a furnace don’t need a separate air handler because the furnace can circulate air through HVAC systems to warm the space.

Air Handler vs Air Conditioner

An air handler and air conditioner are different but work closely together. The air handler takes in the warm air from your home, passes it through a filter, and sends it across the evaporator coils to remove heat and humidity. The fan then blows the conditioned air into the ducts. Meanwhile, the outdoor condenser is another key component of the system that expels the heat that the evaporator coils absorb from the air inside. These units work in sync to keep the air in your home comfortable.

Conclusion

An air handler is a key component of the HVAC system, responsible for circulating air throughout a home’s ductwork. It works in sync with air conditioners and heat pumps, helping to remove heat or transfer heat using evaporator coils. The system uses essential air handler parts like the blower and fan to ensure proper air circulation. 

In homes with furnaces, there’s no need for separate air handlers, as these appliances already include necessary filters, blowers, and fans to circulate air. Some air handlers even come with a heating coil to provide supplemental heat when needed. Understanding these components ensures you’re making the right choices for your home’s comfort and energy efficiency.