Air Compressors Buyer's Guide

Whether you're working on your house or in your shop, Northern's large range of air compressors is certain to include the right one for you. This buyer's guide offers valuable tips and pointers on light to heavy-duty compressors, along with answers to all the questions you may have about buying and using an air compressor.

Advantages of Air Compressors and Air Tools

  • Air tools are more powerful than traditional electric tools
  • Air tools deliver higher torque and higher RPM to help get the job done quickly
  • Air tools are versatile and easily interchangeable
  • Air tools are a safe alternative to other sources

Air Compressor Applications

Home Use
Compressed-air power tools can dramatically decrease the amount of time spent on a project. Many homeowners will use smaller, portable units (either hand-carried or wheeled) that move easily from the garage to the house, yard or roof. Common air tools such as brad nailers, reversible drills, and impact wrenches require about 0–5 CFM (Cubic feet per minute — units in which air flow is measured). It's important to know if the compressor you purchase will drive the air tool you'll need for your project. For example, smaller air nailers run on 2 to 5 CFM at 70 to 90 PSI, while larger shears, sanders require up to 10 or more CFM and 100 to 120 PSI.

Business Use
Air compressors used for business/professional applications are often classified “industrial grade.” They're packed with features that let you take on more demanding jobs with more horsepower, more CFM, more PSI and more (longer) run times. Though some industrial-grade compressors are portable, many are stationary units with large-capacity, ASME certified air tanks (up to 120 gallons), greater HP, more CFM air volume and faster recovery time to run a wide variety of air tools for as long as you need them to do the job.

Air Compressors

How do I determine my CFM Requirements?

The chart below includes some common air tools and their average CFM measurements. Reference this chart to determine what continuous CFM rating is required of your air compressor. Air tools are often rated as “Average CFM.” “Average CFM” is typically based on a 25% duty cycle (15 seconds out of a min.). This sometimes creates a problem with tools that are used on a continuous basis (ex. orbital sanders, die grinders, etc). Nailers and impact wrenches typically don't have the same problem since by their nature are used more intermittently.

If you plan on using an air tool on a continuous basis, it is a good idea to multiply the “Average CFM” x 4 to get a continuous CFM rating for the tool.

Air Tool Description Average CFM @ 90 PSI
Angle Disc Grinder - 7" 5-8
Brad Nailer 0.3
Chisel/Hammer 3-11
Cut-Off Tool 4-10
Drill, Reversible or Straight-Line 3-6
Dual Sander 11-13
Framing Nailer 2.2
Grease Gun 4
Hydraulic Riveter 4
Impact Wrench - 3/8" 2.5-3.5
Impact Wrench - 1/2" 4-5
Impact Wrench - 1" 10
Mini Die Grinder 4-6
Needle Scaler 8-16
Nibbler 4
Orbital Sander 6-9
Ratchet - 1/4" 2.5-3.5
Ratchet - 3/8" 4.5-5
Rotational Sander 8-12.5
Shears 8-16
Speed Saw 5

Air Compressor Power Sources

Electric

Electric air compressors can be plugged in anywhere* and are best used in enclosed areas where gas fumes are unacceptable.

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Electric air compressors
Gasoline

Gas-powered air compressors are ideal for job site pneumatic applications where electrical power is not available. Northern offers compressors driven by reliable Honda or Kohler engines.

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Gas-powered air compressors
*Always know your compressor's required voltage and phase. For example, you can order a 230 Volt, single-phase OR 200, 230 or 460 Volt, 3-phase compressor, depending on available power.

Two-Stage vs. Single-Stage

Two-stage air compressors provide a reliable air source in commercial, industrial and automotive applications. Multistage units tend to be more efficient, compressing air to a higher pressure than single-stage compressors. This allows more air to be stored for future use while generating less heat, reducing wear and extending compressor life.

Features to consider

ASME tank (American Society of Mechanical Engineers)

Belt-driven Air Compressor — Belt-driven compressors generally have a longer life, with less vibration and heat transferring from the motor/engine to the pump.

Cast iron cylinder or cast iron pump sleeves — Cast iron is typically the standard material for cylinders

Fully packaged unit with premounted and prewired magnetic motor start, dual control, belt guard mounted air cooled after cooler and electric condensate drain

Low-oil shutdown prevents downtime and costly repairs resulting from low oil levels

Oil-Free (or Oil-less) compressors are virtually maintenance-free performers for light- to general-duty applications. No need for periodic oil changes.

V-design cylinders — V-design cylinders typically run cooler that in-line cylinders. Heat is a compressors worst enemy.

Vertical vs. horizontal air compressors — Vertical compressors usually take up less floor space than horizontal compressors. Typically, vertical compressors are stationary, whereas smaller horizontal compressors are better for portable applications (such as a truck-mounted compressor).

100% Continuous Speed operation vs. Auto Start/Stop operation — Auto start/stop operation has preset cut in/cut out pressures. The compressor actually stops and turns back on as air is needed. With constant speed operation, the compressor runs 100% of the time and simply adjusts the air output. Dual control compressors offer both auto start/stop and continuous speed operation.

Still need help?
Email our product experts, or Call 1-800-221-0516 our 24-hour sales line.