AHU: Air Handling Unit

What is an AHU?

Definition: What Does the Term AHU Mean?
This term is frequently used to describe a mechanical device that supplies air circulation for heating and cooling. This piece of equipment, handles the air with a fan that moves air into the ductwork and accepts return air from the conditioned spaces. The air handler can be adjusted to accept fresh air from the outside environment or re-circulated air from the conditioned spaces. In the past, this term was most commonly used in the commercial marketplace, however, recently, in the residential marketplace, especially larger homes, AHU’s have become common, and are used extensively. The term AHU is in many cases a RTU ( Roof top unit ) mounted on a curb, located on the roof. In larger projects, several AHU’s can be installed to supply heating and cooling to specific designated areas within the project. A separate thermostat can be installed for each AHU installed, providing what is referenced as zone heating and cooling within the project. The more zones available within a project allows the occupants to adjust the heating and cooling in specific areas within the project. This is a great advantage when several occupants within the same project require different temperatures in their individual spaces. Another method of zoning the heating and cooling is to have electronically controlled dampers within the ductwork distribution to control the amount of air that is distributed to each specified zone within the structure.