Air Handler

An air handler is a key component of heating, ventilation, and air conditioning (HVAC) systems. It plays an essential role in maintaining indoor air quality and comfort by circulating and conditioning air within buildings. 

What is an Air Handler?

An air handler, often called an air handling unit (AHU),is a device that regulates and circulates air as part of an HVAC system. Unlike a furnace or an air conditioning unit, an HVAC air handler doesn’t produce heat or cold air on its own. Instead, it functions as an intermediary, moving pre-conditioned air through the ductwork to maintain consistent air quality and temperature in different parts of a building. Common in both residential and commercial settings, air handlers vary in size and functionality based on the building's specific needs.

Many modern air handlers are equipped with features like variable speed fans, enabling precise airflow control and energy savings. These features make air handlers a crucial part of efficient HVAC systems, particularly in energy-sensitive environments. Some units also have humidity controls, which help maintain balanced indoor moisture levels—a critical feature in climates with high humidity.

 

Components of an Air Handler

An air handler consists of various components that work together to optimize airflow, comfort, and air quality. Key air handler components include:

• Blower Fan: The blower fan circulates air through the HVAC system, drawing air from indoor spaces and pushing it through heating or cooling coils before it reaches the ductwork.
• Heating and Cooling Coils: These coils are responsible for temperature conditioning. The heating coil warms air, while the cooling coil cools it to the desired temperature.
• Filters: Filters capture particles such as dust, pollen, and mold, crucial for air handler maintenance and to maintain indoor air quality.
• Drain Pan and Condensate Drain: These components prevent moisture buildup, especially during cooling, by collecting and draining water, which reduces the risk of mold and system damage.

Additional components may include sound attenuators to minimize noise and dampers to control airflow. Together, these elements make air handlers essential for maintaining a comfortable and healthy indoor environment.

Maintenance and Control

Regular air handler maintenance is necessary for long-term performance. Cleaning coils, replacing filters, and monitoring the blower and fan operations ensure efficiency. Modern air handlers may also have control systems, enabling users to set temperatures, monitor performance, and even integrate with smart home technology. Variable speed motors add another layer of efficiency, adjusting blower speed based on cooling or heating needs to conserve energy and improve air circulation.

How Air Handlers Work?

Air handlers operate by circulating and conditioning air to ensure indoor comfort. The process begins when the blower fan draws air into the system, where it passes through filters to remove contaminants. This filtered air is then either heated or cooled in the coils, depending on the desired temperature.

Control systems play an essential role in regulating the air handler’s functions. Thermostats can signal the unit to activate, adjust blower speed, or modulate temperature settings based on the building’s needs. Additionally, modern air handlers often feature variable speed motors that enhance comfort by reducing noise and allowing for more consistent airflow.

Many air handlers today also include additional features like dehumidifiers, humidifiers, and UV light systems to improve indoor air quality further. For example, humidifiers add moisture to the air during dry winter months, while dehumidifiers reduce excess moisture during the summer, which can prevent mold growth. UV light systems help to purify the air by eliminating bacteria and viruses, making the air healthier and more comfortable.

Types of Air Handlers

Several types of air handlers are available to suit different building requirements:

• Residential Air Handlers: These units are typically smaller, designed to work with split HVAC systems in homes, and are often paired with an outdoor condenser for cooling and a furnace for heating.
• Commercial Air Handlers: Built for larger spaces such as office buildings and shopping centers, these air handlers often feature multiple zones and heavy-duty components to meet higher air circulation demands.
• Modular Air Handlers: These flexible units can be scaled and customized according to the specific needs of large commercial settings, providing both heating and cooling capabilities.
• Packaged Air Handlers: These units house all HVAC components within a single enclosure, making them suitable for compact installations in both residential and commercial settings.

When choosing an air handler, it’s important to consider the building’s requirements, energy efficiency goals, and available space. Selecting an appropriate unit can greatly improve indoor comfort and operational efficiency.

For more information on the various types of HVAC systems, see Most Common Types of HVAC Systems.