Best Air Compressor
The air compressor is the power supply for air tools. Most are powered by electricity, driving a pump that fills an included air tank. This allows the compressor time to rest, while the air is being used out of the tank. The capacity of the air compressor is a combination of the tank size and the amount of air that the unit can compress, measured in CFM (cubic feet per minute).
When selecting an air compressor, it's a good idea to select one that's slightly larger than what you need. As you buy more air tools, your existing compressor will be able to work with them rather than having to upgrade to a larger compressor.
One nice thing about using air tools is they're less expensive and more compact than their electrically operated counterparts since it's much easier to build an air motor since it has fewer parts. Your compressor essentially acts as the power supply for all your air tools as opposed to buying one for each tool.
Air tools are also safer than electric tools which is why they're so common in industrial operations. There is no electrical cord that can get cut, causing the potential of electrocution. and the tool itself can't short out, even if dumped in a bucket of water. While air tools can wear out, they are easily rebuildable.
There are numerous configurations of compressors available on the market, allowing the consumer to select a compressor that best meets their needs. Our buyer's guide listed below will help you pick the compressor which will best work for the way you need to use it.
Best Contractor Air Compressor:
The vast majority of air compressors on the market - except those used for industrial applications - would be considered contractor compressors with this category covering wheeled compressors of any style. While they are mainly used by building contractors, this air compressor category is also ideal for home applications, woodworkers and shade-tree mechanics.
There are three basic styles of contractor air compressors:
- Horizontal Tank Compressors – The most common within this category.
- Vertical Tank Compressors – Like vertical tank shop compressors, these are designed to take up less space
- Wheelbarrow Compressors – These have two smaller diameter tanks, with a single wheel mounted between them at one end. The name comes from the idea that they are moved like a wheelbarrow.
Since compressed air really doesn’t care what size or shape container it’s in, the major difference between these compressors is the convenience for the person using them. If you’re buying a compressor for a home garage, a vertical tank has the advantage of taking up less space. If you’re looking for a compressor that will be used on a construction jobsite, wheelbarrow compressors are less likely to tip over. If you are looking to save money, horizontal compressors offer you the lowest cost.
There are multiple compressor models on the market, even from the same manufacturer. This can make it hard to pick the compressor best for your needs. Other than the physical configuration of the compressor, the major deciding factor usually boils down to the compressor’s specs. Knowing what those specs say can make all the difference in the world.
- Horsepower – This is totally immaterial. All manufacturers put a high enough HP motor on their compressors to drive them.
- Tank Capacity – The amount of compressed air that the tank stores. The larger the tank, the more you can run your tool before the compressor’s motor has to restart. A large capacity tank is better when using tools that require a lot of air or when using the tools a lot.
- Maximum Pressure – Almost all compressors will provide a minimum of 120 PSI air pressure, so this is somewhat immaterial. Air tools are designed and optimized for 90 PSI of supply air.
- Airflow Delivery Capacity – This is the most important specification, and usually the hardest to find. Air tools require a certain amount of air to function and if they don’t recieve enough air, they slow down. You’ll need to select a compressor that has a higher capacity in cubic feet per minute (CFM) than the highest needed by the tools you intend to use with it.
- Duty Cycle – Unless otherwise stated, air compressors are designed for a 60 percent duty cycle. That means that the compressor motor runs 60 percent of the time and is idle for 40 percent of the time; the act of compressing air creates heat, so this is important. If you’re running the compressor at near capacity, causing it to run more than its designed duty cycle, the heat generated by this overage will cause the unit to wear out faster.
Another consideration is whether you buy a compressor that uses oil in the pump or the machine is oil free. There aren’t too many oil free models around but the advantage of an oil free design is if the compressor falls over on its side, there’s no oil to get into the cylinder. However, oil free compressors don’t usually last as long as oiled ones do.
This is one of the largest wheeled compressors around, offering 8.8 CFM at 90 PSI. It only sports a 9 gallon tank, but the pump is quick to recover and replace the air that is used. Read Full Review
The most impressive thing about this line of compressors is they’re incredibly quiet. This model only produces about 60 decibels of sound, putting it at about the same level as normal conversation. Read Full Review
This model from Ingersoll Rand comes with a 30 gallon tank meaning your tools can run longer before the motor has to kick on to recharge the tank. For those that need a lot of air fast, that big tank is nice to have. Read Full Review
DeWalt's compressor is a vertical tank design, taking up less space in your shop, something especially nice for those of you who have smaller workshops. The higher tank pressure means the 15 gallon tank is holding much more air than you'd expect it to. Read Full Review
For those that don't need as big a compressor, Campbell Hausfeld offers this nice 8 gallon model. This compressor will provide 3.8 CFM of air at 90 PSI. Read Full Review
Best Shop Air Compressor:
Of the three basic categories of air compressors, shop air compressors are definitely the largest. They are stationary compressors, designed for use in a shop environment, where several workers might need air at the same time. To accommodate this, they have a larger tank and a larger output volume in CFM (cubic feet per minute).
Without getting into large industrial air compressors, most shop air compressors are vertical. This isn't so much for efficiency as to give the compressor a smaller footprint, using up less of the shop's valuable floor space. There are a few that are still made with horizontal tanks, but those have become rather rare. One is not better than the other in any way, except in the amount of space that they take up. Pressurized air really doesn't care what shape its containment vessel is.
Most of these compressors boast a five horsepower motor. That really isn't important, as the size of the motor has minimal impact on the amount of airflow that a compressor can produce. However, the larger motor requires more power, so these compressors are normally powered by 220 VAC, rather than normal 120VAC house current. That doesn't mean that they can't be used in a home shop however, as homes also have 220 VAC for the clothes dryer, air conditioner and electric stove.
The key, before picking one of these compressors, is to determine how much air volume you need for your shop. The compressor needs to be sized for that need. To make this determination, add the air requirements of all the tools which you expect to have operating at one time. In other words, if you are buying it for a mechanics shop, where three mechanics work, the most airflow requirement you would probably see at one time are three 1/2" impact wrenches, or maybe 2 impact wrenches and a 7" grinder. Some common pneumatic tool air consumption figures are:
- Air hammer, 4 22 CFM
- Brad nailer, 0.5 CFM
- Blow gun, 3 CFM
- Body polisher, 3 CFM
- Orbital sander, 5 CFM
- Cut-off tool, 4 10 CFM
- Die grinder, one-quarter inch, 4 6 CFM
- Disc grinder, 7 inch, 5 8 CFM
- Drill, 3 6 CFM
- Framing nailer, 2.5 CFM
- Impact wrench, one-half inch, 4 5 CFM
- Impact wrench, one inch, 10 CFM
- Mini die grinder, 4 6 CFM
- Paint sprayer, handheld, 3 7 CFM
No compressor should be used in such a way as to be running all the time. They need some time to cool off, as the very act of compressing air creates heat. Normally, compressors are designed for a maximum of 60 percent duty cycle. That means that it should be at rest for at least four minutes out of every ten.
As shop tools, these compressors are not intended to be moved around, and therefore are built without any sort of wheels. Instead, they have feet to stand on. It is highly recommended that these compressors be bolted to the floor before use. Having a compressor fall over would cause severe, possibly irreparable damage, and possibly injury.
While there are bigger and more expensive air compressors on the market than those I've included on this list, I've limited myself to units that I think would be appropriate to a small, privately owned shop or a home workshop. There are a lot of compressors out there, and most of these manufacturers build a whole line of them, so it was pretty hard picking out which ones to include in this list. For the purpose of consistency, I limited myself to units with a 5 HP motor, although many of these companies produce similar compressors with larger motors and capacities.
BelAire makes a great line of compressors, including this 5 HP, 80 gallon one. This is a two-stage compressor, providing lots of pressure and volume. Read Full Review
Campbell Hausfield designs their shop compressors for long life. The pump itself is rated at over 17,000 hours of useful life. Read Full Review
I personally like Rolair's compressors; maybe its the green color. This compressor can operate at continuous duty, not just a 60% duty cycle. Read Full Review
Ingersoll Rand's reputation is enough to cause you to take a good look at their compressors. This model is single stage, but still provides 135 PSI of air pressure. Read Full Review
Chicago Pneumatic is another company with an extensive line of compressors. This one provides 15.3 CFM or air at 100 PSI. Read Full Review
Best Portable Air Compressor:
There’s portable, and then there’s really portable. One person might call something portable because they can move the object with a fork lift, while another might think that object has got to fit in their pocket. For air compressors, portable means it’s designed to be carried. While there are other air compressors that are designed to be wheeled around, they aren’t categorized as portables, but rather “contractor” air compressors.
There are three different designs of air compressors that qualify as “portable”. The main difference between the three is the tank design:
- Pancake – The compressor sits on top of a round, flattened out tank, which usually holds six gallons of air.
- Hotdog – Has a small single tank (about a gallon and a half), shaped like - you guessed it - a hot dog without the ends curling. The compressor is usually mounted alongside the tank.
- Twin Tank - A twin tank has two hot dog-style tanks, one stacked on top of the other. They also have a control panel, for those individuals who prefer that. Most have two air hose connectors allowing two air nailers or other low-volume tools to be attached.
While I’m sure there are many people out there who will tell you one of those three styles is better than another, they’re all about the same and designed to fulfill the same purpose within the same basic price range.
These compressors are designed mostly for contractors, specifically carpenters, who are using them for air nailers. They’re not high volume compressors, but rather intended for use in cases where low volume air is needed; there’s no way you could run an impact wrench or paint sprayer off of one of them.
While manufacturers brag about the horsepower (HP), pressure and tank capacity of their compressors, what you really need to see is the amount of airflow is can provide. Airflow is measured in cubic feet per minute (CFM) and is usually the hardest spec to find, yet the most important. Tank capacity also affects the amount of air that can be used before the compressor needs to restart and they all provide pretty much the same maximum air pressure. Horsepower only affects the amount of air the unit can pump into the tank per minute, and it doesn’t do that in any way which is easily understood or calculated.
The other thing you really want to look at in these compressors is the reputation the manufacturer has for quality. When compressors are used, they’re usually run for long periods of time so one from a quality company will generally last longer than an “el-cheapo” special.
All air compressors use compressor oil, a lightweight machine oil with anti-foaming agents added. Running an air compressor without the oil will ruin it and the other problem associated with oil is it tends to run out if the compressor is tipped over. You want a design that will sit level and not tip over easily. You also want to make sure you place the unit where it’s secure and unlikely to tip over.
Although not as well known, Rolair makes some of the best compressors around. This pancake design has an amazing capacity, delivering 5.4 CFM at 40 PSI or 4.1 CFM at 90 PSI. Read Full Review
This compressor was designed to be quieter than most, running at only 60 decibels of sound pressure. It's an oil-free design, eliminating the biggest maintenance hassle in having a compressor. Read Full Review
This could be one of the quietest compressors in the world, running at only 60 dB. It's also oil-free, eliminating any possible problem of running out of oil. Read Full Review
For a hotdog compressor, this one has a lot of capacity, offering 2.8 CFM of air at 90 PSI. The design included an integrated roll cage, making it incredibly rugged for use on the job site. Read Full Review
For such a small compressor, this one offers a big capacity. It provides 3.8 CFM of air at 40 PSI or 3.3 CFM at 90 PSI.The secret is the "big bore" pump which provides more air per stroke than similar sized compressors. Read Full Review
Air Compressor Buyer's Guide
Anyone who uses any sort of air tools, from air nailers to impact wrenches, needs a compressor to power them. What type of compressor and how big a compressor are questions that may be hard to answer. Nevertheless, they have to be answered in order to pick out the best possible compressor for your needs.
While there are many ways of compressing air, the standard way used for air compressors is via a piston. The piston works much like the piston on an engine, packing the air into about 1/8 of its original volume. This compressed air then leaves the piston and is stored in a tank. By using a tank, the compressor is able to supply bursts of air which are a much higher volume than the compressor can produce.
Air compressors are typically designed to compress the air to 120 PSI, the maximum most air tools are designed to handle. However, air tools are typically rated for operation at 90 PSI, so you’ll see many air compressor specifications listed at this pressure. Manufacturers usually list specs for two pressures, 30 PSI and 90 PSI respectively.
Air Compressor Types
Due to the high number of different air compressor models available, there are actually many different ways of categorizing air compressors,. Air compressors are used in home workshops, woodworking shops, and mechanics shops, as well as extensively in heavy industry as well. For the purpose of this buyer's guide, we are concentrating primarily on air compressors that would be used by a do-it-yourselfer or a contractor, not industrial-model compressors.
There are three basic categories of compressors to choose from, with several different styles within each of these categories which include the following:
Meant to be carried. These compact compressors are used where not a lot of air volume is needed, mostly by finish carpenters for their air nailers.
The “mid-range” compressor, used by everyone from building contractors to do-it-yourselfers. These are wheel mounted so that they can be brought to the place where they are needed.
Shop air compressors are fixed location compressors which are used to provide air to several people working in the same shop. They are large units, which can provide a large quantity of air and have larger tanks.
Contractor compressors traditionally have a horizontally mounted tank and shop compressors typically have a vertically mounted tank. This allows a smaller footprint for the shop air compressor. Recently, manufacturers have started making contractor compressors with vertically mounted tanks as well, specifically so that they will take up less room in a workshop.
Other Types of Compressors
Although we don't list them, because they are designed for industry, there are a couple of categories of compressors that you should be aware of, just so that you will recognize them if you see them.
Gasoline Powered Air Compressors
Contractors working on a construction site may need to use an air compressor where there is no electrical power. Their options are to bring along an electrical generator or to use a gas powered air compressor. There are also diesel powered compressors, which are essentially the same, but designed so that they can be installed on a vehicle that uses diesel fuel instead of one that burns gasoline. Either type of gas powered compressor is much more expensive than an electrically driven one.
Multi-stage air compressors are used in industrial facilities where a large volume of high pressure air is needed. These are very large compressors that compress the air in stages, allowing them to produce a much higher final air pressure. Typically, the air pressure is regulated downward for use in tools.
Important Air Compressor Specifications
Cubic Feet Per Minute (CFM)
Most manufacturers tout the horsepower rating of their compressors, but that’s really not the important specification. The important one is the amount of air that the compressor can continually supply, measured in cubic feet per minute (CFM). The CFM of the compressor has to be higher than any of the tools which are connected to it. If not, the compressor won’t be able to keep up and the tool will slow down, losing power as well.
Shop compressors have a higher CFM rating and are normally intended for several air tools to be connected to them at the same time. In such a case it is necessary that the rating of the compressor be higher than the total of the average air usage of the tools.
By average air usage, I'm referring to the duty cycle. If you connect ten tools with the same air volume requirements to an air compressor, but each is only used ten percent of the time, it's the same as only having one tool attached to the compressor. So, you must consider duty cycle when you are determining the total volume of air required for these larger compressors.
Unless a compressor manufacturer specifically states that their product is designed for a 100 percent duty cycle, you can assume that it is designed for a 60 percent duty cycle. That means that the compressor’s motor shouldn’t be running for more than 60 percent of the time. If it does, the unit will produce more heat than it can dissipate, causing damage to the compressor.
Tank size is important in that the compressed air in the tank is the reserve you have. Your tools will draw air from the tank, which will then be replenished by the compressor. A pressure switch turns on the compressor motor when the air pressure in the tank drops to 95 PSI.
Horsepower and maximum pressure are normally stated for compressors, but are not important specifications. The manufacturer will select a horsepower rating that is high enough to drive the compressor. The main reason that the horsepower rating is given is to impress potential customers.
Any air compressor consists of the compressor itself, a motor to drive the compressor and an air tank. How the air compressor and the tank are physically connected together is not as important as that they are. However, through the years, a number of different styles have been developed, giving more variety to the number of compressor models on the market. Some configurations are easier to work with in certain situations than others.
Pancake compressors are small, portable compressors, with six gallon tanks. The name comes from the basic shape of the tank. The compressor is mounted above the tank, making a compact unit.
Hot dog compressors are another type of portable compressor. They use two small horizontal tanks, stacked. The compressor is usually a small one and sits on top of the tanks. These are about the only compressors which are likely to have a control panel.
Wheelbarrow compressors are contractor compressors with two thin horizontal tanks. The name comes from the singe wheel which is mounted at one end, between the tanks. Twin handles are attached to the other end. This makes moving the compressor much like moving a wheelbarrow. The low profile of these compressors makes them ideal for loading in the back of a pickup truck with a bed cover.
The horizontal compressor is the standard contractor air compressor configuration, with a large horizontal tank and the compressor mounted above the tank. They tend to be unstable and tip over easily.
Shop compressors are usually vertical compressors, with a large vertical tank and the compressor mounted above it. This allows for a larger tank, reducing the duty cycle of the motor. Some smaller vertical compressors have wheels, allowing them to be moved like a hand truck.