Air Handling Units

Air handling units (AHU), are a HVAC item of plant that is used to regulate and circulate air as part of a heating, ventilating, and air-conditioning system. An AHU usually houses a fan, heating or cooling elements, filter chambers, heat recovery units, humidifiers, sound attenuators, and dampers. Air handlers usually connect to a ductwork ventilation system that distributes the conditioned air through the building and returns it to the air handling unit.

Smaller AHUs, used in localised applications, are called terminal units, and may only include an air filter, coil, and blower. These simple terminal units are called fan coil units. A larger air handler that conditions 100% outside air, and no recirculated air, is known as a makeup air unit (MAU). An air handler designed for outdoor use, typically on roofs, is known as a packaged unit (PU) or rooftop unit (RTU).

Controls are essential to regulate all aspects of an AHU, such as flow rate of air, flow of hot or cold liquid through control valves, supply air temperature, mixed air temperature, humidity, air quality. They may be as simple as an off/on thermostat or as complex as a building automation system using BACnet, MODBUS or LonWorks.

Common control components include temperature sensors, humidity sensors, actuators, motors, and controllers.

Recommended Installations

Pressure Independent Control Valve (PICV)

Stand Alone


  • Easy to set up
  • Straightforward commissioning
  • No need for separate Commissioning Set and 2 Port Control Valve
  • Size available up to DN150
View PICVs

Hook-Up w/ PICV


  • Can be remotely fitted away from the terminal
  • Reduced space constraints
  • Extended levers available for chilled systems
  • Sizes available up to DN25
View Hook-Ups

– Or –

Differential Pressure Control Valve (DPCV)

Stand Alone


  • Range of controllable dPs Available
  • Available with Companion Valve
  • Sizes available up to DN150
View DPCVs

Hook-Up w/ Comm. Set

w/ Comm. Set

  • Available with either static Commissioning Set or Motobalance
  • Available with Strainer
  • Extended levers available for chilled systems
View Hook-Ups

Product Applications

Select from the product applications below to find out how dynamic balancing can improve installation on on-going operation.