The definition of a HVAC duct temperature is the temperature of the air that is flowing through the ducts of a heating, ventilation, and air conditioning (HVAC) system. This temperature is important to monitor in order to ensure that the air is at a comfortable temperature for the occupants of the building. It is also important to monitor the temperature of the air in the ducts to ensure that the HVAC system is operating efficiently and that the air is not too hot or too cold. The temperature of the air in the ducts is typically monitored using a thermometer or other temperature-sensing device. The temperature of the air in the ducts should be kept at a comfortable level for the occupants of the building and should not exceed the maximum temperature specified by the manufacturer of the HVAC system.