Anemometers read air velocity in m/s, km/h, mile/h, knots or ft/min and air volume in CFM or CMM plus temperature in °C or °F. AFC offers two basic types of Anemometers including Hot Wire and Vane styles. The Hot Wire heats a wire to a specified temperature and then measures the rate of cooling. These units have a fast response time but are delicate. The vane style works on the principle of a freely turning turbine that will rotate at a speed directly proportional to the wind speed.