The AHU, or Air Handling Unit, is an essential component of a modern HVAC system. It is responsible for controlling the air temperature, humidity, and air quality in a building. The AHU is composed of several components, including a fan, filter, and heat exchanger. The fan is responsible for circulating air through the system, while the filter removes dust and other contaminants from the air. The heat exchanger is responsible for heating or cooling the air, depending on the season. The AHU also includes dampers, which are used to control the amount of air that is circulated. By controlling the air flow, the AHU can maintain the desired temperature and humidity levels in the building. The AHU is a critical component of a modern HVAC system, and it is essential for providing a comfortable and healthy environment for occupants.