First, Determine Business Needs
As with any other piece of capital equipment, the purchase of an air compressor requires some research. Once it is determined that an air compressor can add to the efficiency of an operation, each business must identify the type best suited to it. Or perhaps an air compressor has been in operation already, but needs to be replaced or upgraded.

A Little Air Compressor Background
Air compressors are of three basic types: reciprocating, rotary screw, or rotary centrifugal. Each type of air compressor is further specified as single-stage or two-stage compression; whether it is powered by electric motor, engine, or other; how it is cooled, and how it is lubricated. For air pressure requirements of 70-100 PSI, a single-stage air compressor is typically used, while a two-stage compressor provides pressures of 100-250 PSI.

Tailor the Equipment to Its Use
In a small shop, an electric reciprocating unit may be perfectly suitable. If an air compressor is needed on remote job sites, a self-contained unit with a power source, may be ideal. Power sources could be either a gas air compressor or a high-capacity storage battery.

Stationary Air Compressors
Shop air compressors range from light-duty, small capacity reciprocal units that typically utilize a 15-20 gallon tank and operate on 110 volt electrical power to medium/heavy duty units with tank capacities of 60-80 gallons and 230 volt requirements. For a small shop with 1-3 employees and light usage for tasks involving air-powered hand tools, a light duty electric air compressor will cost in the $200-$400 dollar range. The larger medium/heavy duty reciprocal air compressors start at just under $1,000 and can cost as much as $2,000 and up. If a shop has four or more employees, or operates machinery using compressed air, one of these higher-capacity units may be essential.

For even larger operations, a rotary air compressor may be required. These units are used for large air-powered production equipment and central compressed-air systems. They range from general-specification compressors to custom-built systems, and can range from $15,000 to six figures, depending on the capacity required.

Portable Air Compressors
A business may also require compressed air on remote jobsites. There are a number of portable air compressors that are suitable for this application. These range from small units with a two-gallon tank capacity to large stationary or truck-mounted air compressors that may be two-stage units. There are many portable and wheelbarrow electric air compressors which are suitable for jobsites where electrical power is available. Many of the larger units have small gasoline engines, typically made by Briggs andamp; Stratton, Kohler, or Honda. Gasoline air compressors are used at jobsites where electric power is not available. Prices range from around $200 for the smaller two-gallon portable air compressors to over $2,000 for large truck-mounted units. As in selecting an air compressor for shop use, it is important to evaluate present and future requirements to ensure that the unit selected has sufficient capacity to do the job.

Sources
Air Compressors Direct
The Engineering Toolbox