A single duct terminal unit (SDTU) is a type of air-handling unit that is used to control the temperature and air quality in a single room or space. It is typically installed in commercial buildings, such as offices, retail stores, and restaurants. The SDTU is a self-contained unit that is connected to the main air-handling system. It is responsible for regulating the temperature, humidity, and air quality in the space. It is designed to provide the necessary air flow and temperature control to maintain a comfortable environment. The SDTU is also responsible for filtering the air to remove dust, pollen, and other airborne particles. It is typically equipped with a filter to ensure that the air quality is maintained. The SDTU is an important component of the air-handling system and is essential for providing a comfortable and healthy environment.