How to Choose a Portable Air Compressor

Portable air compressors give flexibility to the job both inside and outside the working environment. They're powered by electric, gasoline or diesel engine. A larger portable air compressor often has its own carrying trailer with wheels and handles. You buy a compressor based on its horsepower, pounds per square inch (PSI) and cubic feet per minute (CFM). Choose a portable air compressor to make work quicker and easier.

Difficulty: Moderate

Instructions

1. Figure the amount of power you need based on the type of job and air tools used. Know the cubic feet per minute (CFM), such as 5 CFM for small household tools and 10 CFM or more for wrenches or sanders. All air tools have these ratings.

2. Select a gas- or electric-powered engine. Gas gives a higher reliability for frequent use and portability, but consider electric for enclosed areas for its lack of fumes.

3. Pick an air tank based on amount of use time and tools. Large tanks are best for longer use with sanders or grinders and smaller tanks for less time, like wrenches and air hammers.

4. Consider the pump type you need: belt for heavy use or direct-drive for light home use. The quieter belt-drive pump needs periodic oil changes.

5. Buy an inexpensive, small electric portable air compressor for small jobs. These typically operate from a 12-volt power outlet and inflate a 14-inch tire in a few minutes.

6. Get a 150 PSI, 120 volt motor pancake-type air compressor for home use. These light-use models typically carry two air couplers, allowing hook up of two air tools and adequate 25 feet or more air hose.

7. Obtain a larger PSI portable air compressor for bigger jobs, like nailing, with longer continuous use capabilities.

Tips & Warnings

• Know the CFM requirements of your tools before you buy a compressor and add a margin of safety of 50%. Each tool has the needed CFM on its box and the portable air compressor must meet that for proper use. For example, if your tool rates 4 CFM at 90 PSI, the compressor must deliver 6 CFM.
• Get a single-stage piston compressor for most home jobs. These deliver up to 150 PSI and are considered light-duty. A two-stage unit, mostly for commercial jobs, rates over 150 PSI for continuous jobs.
• Consider an oil-lubricated compressor for heavy use.
• Air tools deliver more power with less weight and have a lower cost than regular electric tools.
• Never use tools without proper eye protection, and for gas-powered compressors, use earplugs.