An AHU (Air Handling Unit) is a critical component of any HVAC system. It is responsible for taking in outside air, filtering it, heating or cooling it, and then distributing it throughout the building. An AHU is made up of several components, including a fan, a filter, a heat exchanger, and a control system. The fan is responsible for drawing in outside air and pushing it through the system. The filter is responsible for removing any contaminants from the air. The heat exchanger is responsible for heating or cooling the air, depending on the season. Finally, the control system is responsible for regulating the air flow and temperature throughout the building. An AHU is an essential part of any HVAC system, as it ensures that the air in the building is clean, comfortable, and safe.