What device is used to measure air flow in ductwork?

The device used to measure air flow in ductwork is an anemometer. An anemometer specifically gauges the velocity of air moving through a system, which is crucial for ensuring proper airflow and system efficiency in HVAC applications. By measuring air speed, it can calculate the volumetric flow rate of air within the ductwork, helping technicians identify if the system is operating within its intended parameters.

Other devices listed are used for different purposes: a barometer measures atmospheric pressure, a manometer measures static or dynamic pressure in gases, and a thermometer measures temperature. While all these measurements are important in HVAC diagnostics and system performance, they do not directly measure airflow in ductwork like an anemometer does.