An air handler is a part of an HVAC system that circulates conditioned air throughout your home. It works in conjunction with an air conditioner or heat pump to distribute cool or warm air.
Depending on the type of HVAC system installed at home, an air handler can be part of either a ducted or ductless system, such as a mini-split. In case of a central system, air handlers are typically installed in areas such as the attic, basement, or a utility closet. In mini-split systems, the air handler, also called the indoor unit, is installed directly inside your room.
How Does an Air Handler Work?
An air handler pulls the indoor air in, conditions it, and then pushes it back out through ducts or individual indoor units (mini-splits), keeping your home at the desired temperature.
Here’s a breakdown of how it works:
- The air handler draws in indoor air through the return vents or individual indoor units.
- The air passes through a filter that removes dust, allergens, and debris.
- It then passes over the evaporator coil, where the refrigerant absorbs heat, producing cool air.
- The blower fan then pushes this conditioned air through the ducts (in a central system) or directly into the room (in a ductless mini-split system).
- The cycle is repeated to maintain your preferred temperature and comfort level.
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Main Components of an Air Handler
Air handlers contain various components such as an evaporator coil, a blower, an air filter, and a drain pan.
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Evaporator Coil
The evaporator coil is the main component where heat exchange takes place. It contains the refrigerant, which absorbs heat and humidity from the indoor air as it passes over the coil’s surface. This process cools the air before it’s circulated back into your home, helping to maintain a comfortable indoor temperature.
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Blower & Fan
The blower powers the fan that circulates conditioned air throughout your home. Some units use variable-speed blowers that adjust for quieter operation and improved efficiency.
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Air Filter
During the air conditioning process, the air passes through the filter, which traps dirt, dust, and other particles to maintain clean indoor air.
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Drain Pan & Condensate Drain
As warm, humid air passes over the evaporator coil, moisture naturally condenses. This water is collected in the drain pan. The condensate drain then moves this moisture from the top of your system. These components help prevent water buildup, leakage, and damage to the air handler.
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Damper
If you want specific zones in your home to cater to various heating/cooling needs, you can install dampers. They regulate the airflow within the air handler and direct conditioned air to the specific zones. Depending on the setup, dampers can be manual or automatic, controlled by a smart thermostat.
Different Types of Air Handlers
1. Single-Stage Air Handler
Single-stage air handlers operate at one fixed speed. They are either fully on or off and are a part of a single-stage HVAC system. They are less energy-efficient because they run at full capacity, and their airflow cannot be adjusted to match demand. They are affordable, but lead to high bills over time.
2. Multi-Stage Air Handler
Multi-stage air handlers offer multiple speed settings to cater to varying temperature needs. They can run at lower speeds when less heating or cooling is needed and switch to higher speeds for extreme conditions. This flexibility allows better temperature control and improved energy efficiency compared to single-stage units.
3. Variable-Speed Air Handler
Variable-speed air handlers deliver the highest level of efficiency and comfort. These systems automatically adjust their fan speed to maintain a consistent indoor temperature and optimal airflow. By operating mostly at lower speeds, they reduce noise and consume less energy. While variable-speed models have a higher upfront cost, they provide long-term energy savings and improved comfort.
An air handler is essential for filtering and circulating conditioned air throughout your home. Understanding its components and types helps ensure efficient performance, consistent comfort, and better indoor air quality.