Anemometers are used to measure air and gas flows in a variety of applications, including such tasks as the balancing of HVAC systems using hand-held air velocity meters. They are also used in stacks to measure the velocity of wet and dirty gases and in wind detection applications to obtain three- dimensional wind velocity profiles using Doppler-type sen- sors. Anemometer designs include pitot, mechanical (vane, cup, propeller, turbine), thermal, and Doppler types.