Caryaire VAV terminal Modulates the airflow volume of the occupied space at a constant temperature based on the cooling demand. As the air conditioning load increases in the area due to an increase in the occupancy or any other reason the air volume of the supply air through the VAV box increases and vice versa. VAV Boxes can be used with duct systems with Static pressures up to 3” wg and the Air Volume range is from 50 CFM to 7000 CFM.