Fans and blowers are commonly used to move air and other gases. They come in a wide range of shapes and sizes and may be axial, mixed flow or centrifugal in nature. The equipment is used in many industries including HVAC, power generation, process and transportation.

Blowers differ from compressors in that the pressure ratio is generally lower, and fluid compressibility is usually less significant.

Like other rotating equipment, fans and blowers must be efficient. Other important factors include operating range, compact size (particularly when used in transportation applications) and limited noise output (such as for HVAC supplications). Additionally, manufacturing costs often restricts design options, further challenging the product designer.