What is the definition of a supply air sensor? A supply air sensor is a type of sensor used in heating, ventilation, and air conditioning (HVAC) systems. It is used to measure the temperature of the supply air that is being provided to a given space or area. It is also used to detect changes in the air temperature so that the HVAC system can adjust the air conditioner or heater to maintain the desired level of comfort. Supply air sensors are typically placed near the supply duct, return duct, or in the space itself. They can be either digital or analog and come in a variety of sizes and shapes. In addition, the sensing type and the material of the sensor must be chosen based on the environment in which the sensor is located. The most common types are thermistor, RTD, and thermocouple sensors. Generally, thermistor sensors are the most common and are used to measure temperature changes in the air. RTD and thermocouple sensors