Air Compressor Buying Guide

The way air compressor specifications are described may seem complicated, but there are six important spec to look at.

Oil-Lube vs Oil-Free

All air compressors either use oil as a lubricant or are oil-free, and use advanced polymer rings. The traditional oil-lube air compressor requires regular oil changes and replenishment, and if used for painting or woodwork, may require an oil trap to avoid damaging your materials. Newer, oil-free compressors require less maintenance and generally run cleaner, but the lack of oil lubrication means they may have a slightly shorter service lifespan. Many people prefer oil-free for simplicity and ease of use.

PSI (Pounds per Square Inch)

A measure of how densely packed the air is inside the compressor tank. Some tools require a minimum pressure to operate. Make sure to choose a compressor that has a high enough PSI rating to support the tools you intend to use.

• 60 PSI and below – cleaning, inflation, spray painting
• 60-100 PSI – normal air tool operating range
• 100-130 PSI – for use when longer hoses or when more power is needed
• Over 130 PSI – for use with specialty tools designed for use with high pressure

SCFM (Standard Cubic Feet per Minute)

This measures the rate at which air flows into and out of the compressor tank. Every air tool consumes air at a certain rate. The more SCFM your compressor provides, the more tools you can run simultaneously, or the higher duty-cycle you can run them.

Examples of SCFM requirements of common air tools:

• 0.7 SCFM – Brad Nailer
• 2.4 SCFM – Finish Nailer
• 3.0 – 5.0 SCFM – Framing Nailer
• 5.0 – 7.0 SCFM – Paint Sprayer
• 9.0 – 15.0 SCFM – HVLP Paint Sprayer
• Up to 20 SCFM – 3/8" Air Ratchet
• Up to 35 SCFM – 1/2" Impact Wrench

Keep in mind your air tool will utilize the scfm from the pump PLUS the stored air in the tank to achieve maximum tool performance and run time. However, if the compressor is not matched properly, it may be necessary to run the air tool intermittently which will lower SCFM required, or the tool may not achieve proper power level.

HP (Horsepower)

The power of the motor running the compressor is measured in horsepower. Smaller compressors with lower scfm and PSI need smaller motors, and larger compressors need larger motors. While horsepower is important, the SCFM rating along with tank size and max PSI are more telling of the power of the air compressor.

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BA (Weighted Decibels)

The noise produced by a compressor is measured in decibels. While larger compressors are inevitably noisy, many modern compressors have become very quiet. If you’re going to be working near an air compressor, or for long periods of time, consider low-noise compressors.

• Under 60 dBA – volume of typical conversation, very quiet compressor
• 60-80 dBA – volume of a restaurant, medium quiet compressor
• Over 80 dBA – volume of a vacuum cleaner or above, noisier compressor

Pressure Drop

The reduction in air pressure from the compressor to the tool. Flow restrictions caused by the regulator, couplers, or undersized air hose, require higher operating pressures to be regulated at the compressor, in order to get the desired target pressure to the tool.