Definition

• An air handling unit, also known as an AHU, is a device used to condition and circulate air as part of a heating, ventilating, filtration and air-conditioning system. An air handler is a large metal unit that contains many components related to a ventilation system. A blower, heating or cooling elements, filter racks or chambers, sound attenuators and dampers all comprise the main functions of an air handler.
  
  

Benefits to an Air Handler

• Air handlers improve the quality of air indoors using a air filtration system. Most people spend the majority of their day indoors, and a high level of air quality is important. An air handler can work to remove dust, mold spores, animal bacteria, pollen, dust mites and lint from the air.
  
  

Air Cleaning Process

• The air handler cleans air through a complex filtration system. Most air handlers have a three-step process that can eliminate 99 percent of harmful particles in the home. First, the filtration system traps large particles of air. To trap smaller particles, air passes over electrically charged corona fields. The passing air is trapped in the system and passed through tiny filters.
  
  

Heating Process

• Air handler heating systems have a primary heating appliance that acts solely to provide heat. These heating units consist of four main components: burners that deliver and burn fuel, heat exchangers, a blower and a flue that acts as an exhaust for gaseous by-products. Air from the space blows across the heat exchanger to be warmed. It is then blown through a system of ducts that distribute heat around the space.
  
  

Cooling Process

• The most common central cooling system in an air handling unit is a split system, which includes an outdoor cabinet containing a condenser coil and compressor. The compressor pumps a chemical called refrigerant through the system. Once warm air inside your home blows across the indoor evaporator coil, its heat energy transfers to the refrigerant inside the coil. That transfer cools the air and cool air is pumped out.