You’ve heard of these HVAC units, but what exactly is an air handler, and how does an air handler work?

An air handler, or air handling unit, is a metal box that contains all the components needed to move cooled or warmed air through a building, temporary structure or space. Unlike an air conditioner or heater, it doesn’t directly cool or warm the air.

Air handlers sit indoors and are typically paired with a water chiller, heat pump or air conditioner via ductwork. The cooled or warmed air passes into the air handler, which uses an electric-powered blower to move it through the duct system and into the area that needs climate control.

Some air handlers contain evaporator coils that remove additional heat and moisture for cooling purposes. For additional heating, electric heating strips can be added.

The blower motor may have one speed or variable speeds. Air handlers with variable speeds adjust on the fly to provide more air flow when needed. Air handlers typically also contain an air filter to remove airborne particles.

Units are sized by cubic feet per minute and/or tonnage. In rental fleets, they range in size from 10 ton to 150 ton.

When are air handlers used?

Air handlers can be used for temporary and permanent HVAC solutions, especially when cooling is needed.

“They are usually used in larger cooling projects, in special applications and where air temperature needs to be lower than 60° Fahrenheit,” said John Helsing, west region product development manager for United Rentals Power & HVAC. Air conditioners can’t cool the air below 60F.

Large air handlers are ideal for factory floors, warehouses and other industrial spaces, Helsing noted.

Flexible, cost-efficient solutions

Air handlers enable creative climate control solutions that can save organizations money.

United Rentals worked with one client to heat a university garage using plant steam. An air handler was installed to harness this energy-efficient heat source. In the four months the air handler was on site, the client saved $100,000 compared to the cost of warming the garage using heaters.

How to choose an air handler

Air handlers are categorized by cubic feet of air flow per minute and/or the amount of heat they can remove from the air per hour. A 120-ton air handler, for example, removes up to 120 tons of heat per hour, with air flows of up to 30,000 cubic feet per minute. A 75-ton air handler removes up to 75 tons of heat per hour and produces an air flow of 7,000 cubic feet per minute.

Large air handlers often have forklifts pockets for easy positioning.

When choosing an air handler, also consider their power requirements. Most air handlers run on 460 volts.

Helsing recommends working with an HVAC rental professional to identify the air handler that will achieve your desired result. When he’s helping United Rentals customers choose an air handler, Helsing considers:

• The size and shape of the space being cooled, including the length, width and height

• The ambient air temperature and the heat load inside the space

• The desired space temperature

• Availability of power and water supply

• Space available for equipment

Air handlers are versatile units that can meet a range of HVAC needs, from providing very cool air to harnessing energy-efficient heat sources. Talk with an HVAC expert to learn if an air handler is right for your space.

Visit our online marketplace to browse air handlers and subsystems, or call us at 833.347.6180 for help in choosing the right air handler or to place an order and schedule installation.