Air Compressor Buying Guide – How To Select The Best One
Picking the Perfect Air Compressor For Your Needs
Before you pick the perfect air compressor for a particular job, it is essential to know your options. Following are the things in general that you should know about air compressors:
Types of different air compressors
- Criteria you should look for in an air compressor
- Choosing the perfect air compressor for a specific purpose
No worries! We will guide you through each of these topics so that you can make educated decisions while purchasing air compressors.
Air Compressor Types
Reciprocating Compressor
Reciprocating compressors are most commonly used, especially for home usage and small workshop setting. These are positive-displacement compressors that draw air into the cylinder and use pistons to compress the air.
These can be powered either by an electric motor or a gas engine. These compressors are easy maintenance, inexpensive, and has a long lifespan compared to most other compressor types.
As the internal components of these compressors are susceptible to friction, the device may run hotter and create noise. Most reciprocating compressors use lubrication, whereas there are some oil-less options available.
You can choose either a single-stage or two-stage reciprocating compressor, based on your preference. Single-stage compressors compress air in single piston stroke, up to a pressure of 120 PSI. In contrast, two-stage compressors use a secondary piston for further compression for a pressure level of up to 200 PSI.
Rotary Compressor
Rotary air compressors have been a popular choice, especially for heavy-duty or industrial applications. They can be of four types: screw type, scroll type, vane type, and lobe type. However, the rotary screw type compressors have been prominent in the market for a long time.
Rotary compressors rely on two helical rotor screws instead of pistons to compress air. These screws intermesh to reduce the volume of the trapped air is, and thus the compression takes place.
These compressors offer both oil-injected and oil-free options. Nevertheless, these are more energy-efficient, reliable, and much quieter than equivalent reciprocating compressors. Moreover, you will find a great balance in their price, efficiency, and power.
Scroll Compressor
Scroll compressors have a rotary spiral design with two spiral-shaped circular pieces. One scroll remains stationary while the other moves in a circular motion without rotating. This unique, compact device can cool a large volume of air much faster than most other compressors.
As the scrolls in these compressors do not need to touch, no lubrication is required. Thus scroll compressors can offer you a 100% oil-free operation.
Consequently, it eliminates the risk of air contamination and delivers you clean air. Besides, this operation is completely noise-free!
Scroll compressors offer you superior efficiency, energy-savings, excellent durability, and reliability. Due to having fewer parts, these compressors are less prone to mechanical failure. Hence you will need minimal maintenance over time.
Scroll compressors have a wide array of applications, from refrigeration to turbos in high-performing vehicles. Because of oil-free design with quiet operation, they are superb for electronics, pharmaceutical, dental, and food industries.
Twin Stack Compressor
Twin-stack air compressors consist of two air tanks, which means you can reserve more air. As a result, the compressor does not have to run as often, leading to enhanced efficiency and lifespan.
This kind of air compressor is suitable for average homeowners. They are excellent for inflating tires and powering air tools, e.g., brad guns, staplers, etc.
Pancake Compressor
Pancake air compressors are exceptionally convenient in terms of storage and portability. These kinds of compressors are small and lightweight.
For instance, tank size can be as small as 1 gallon, and they hardly weigh more than 35 pounds. So you can imagine how handy these are to move around!
These compressors are appropriate for your around-the-house use, such as airbrushing; filling tires, rafts, or sports balls.They typically have an oil-free design with no belts, hence they are quite low maintenance. One con side could be the noise level of this compressor.
Hot Dog Compressor
Hot dog compressors are somewhat larger than pancake compressors and thus little bit heavier. Most of these compressors have a built-in carrying handle to facilitate transportation.
They are sufficient to provide power to small pneumatic tools such as stapler, air brushers, etc. That is why they are preferred by hobbyists, while they also work well for garages and outdoor operations.
Similar to pancake compressors, these are oil-free and does not have belts. Because of direct drive, they usually vibrate and create noise. Try to go for some rubber feet that help prevent the compressor from moving and amplifying the noise level.
Nonetheless, there are also some quieter options available, which promote minimum wear and longer life of the devices.
Buyer’s Guide: What to Look For
There are several criteria you should look for to find the most appropriate compressor for your specific purpose. Check these criteria discussed below before you make your ultimate decision about buying an air compressor.
Tank Size
The tank size of a compressor regulates how long the pneumatic tool can run before the compressor turns back on. The tank volume measures in gallons, ranging from 1 gallon to 80 gallons.
Small tank sizes will be good enough if you are planning to use air tools intermittently. For example, 2-6 gallons tank volume should be sufficient for a nail gun that needs a single burst of air. Likewise, merely 1 gallon works quite well for simple jobs like inflating tires or balls.
Conversely, for continuous use of tools requiring a higher volume of air, you should definitely go for larger tanks. For instance, painting, grinding, etc. may require a tank volume of 60 gallons! Besides, if you have multiple tools to use at a time, that should also be taken into account.
Pounds per Square Inch (PSI)
pounds per square inch is a measurement of air pressure that is delivered by an air compressor. The higher the number the higher the volume of air that can be compressed into a tank.
Cubic Feet per Minute (CFM)
Cubic feet per minute is the volume of air delivered in one minute of an air compressor running at it’s optimal conditions. There are several different CFM ratings out there but make sure you are looking at the delivered CFM as that is the actual volume of air that will reach the end of your hose and your tools.
In general, the tank size should be large enough to accommodate more CFM than the required CFM for the tools. Thus, this excess CFM allows the compressor to have some time to cool down and prevent from overworking.
Power Source: Electric Vs. Gas
As already mentioned, air compressors can be powered either by electricity or gasoline. Let’s have a look at how this affects the compressor characteristics.
Electric compressors
Electric compressors are more commonly used compared to gas-powered compressors. They are less costly and more convenient, particularly if the site has a power outlet.
These compressors are quite versatile in terms of styles and sizes and are typically lightweight. They do not emit any fume, hence ideal for indoor uses such as repairs, trim and finish work, etc.
In general, they run on standard household voltage, i.e., 110-120 V. However, it may vary and range up to 220-240 V, depending on the horsepower. One thing to keep in mind that powering with a generator may hamper the performance of the compressor in the long run.
A clear drawback for electric compressors is that they will not work in locations where there is no power outlet. Also, they may not be the best choice for heavy-duty applications.
Gas-powered compressors
As you know, gas-powered compressors use gasoline for power, usually when electrical plugging is not an option. Besides, they are also suitable for distant use with an extension cord.
These compressors can operate continuously, making them ideal for medium to heavy-duty industrial applications. Typically this type of compressor is used by builders, remodelers, etc. Unlike electric compressors, they are usually heavy and bulky.
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As a downside, these compressors generate are noisy and exhaust fumes. Moreover, gasoline can be highly flammable, requiring caution and maintenance. Therefore they are not recommended for indoor use.
Oil-lubricated Vs. Oil-free
Oil-lubricated air compressors require oil to lubricate the piston chamber or screws to prevent excessive friction, wear, and consequent overheating. This type of compressor needs an oil change and filter change from time to time to avoid premature failure.
Monitoring and maintenance are required so that oil does not seep through and contaminate the air. These compressors are typically at the heavier and costlier side.
However, note that oil-lubricated air compressors last longer compared to oil-free ones. Moreover, they are much less noisy because of being well-lubricated.
Oil-free compressors are pre-lubricated with materials such as Teflon, which serves as a permanent lubricant. Therefore, there is no need to change oil frequently, also chances of air contamination are unlikely.
As there are lesser parts, these compressors are relatively smaller, lighter, and inexpensive. Thus, oil-free compressors will be perfect for your home use or if portability is a preference to you.
There are a few disadvantages associated with this kind of compressor. The coated lubricants in an oil-free compressor may wear out over time, and the compressor can run hotter and louder. These compressors may not last as long as oil-lubricated ones.
Portability – Portable Vs. Stationary
Portability can be a significant factor to consider while buying a compressor. Based on your intended application, you may choose a portable or a stationary compressor.
Portable compressors usually are of small capacity and light enough to be easily carried to a site or stowed away. If you are a homeowner and contractor, you may like a pancake, twin-stack, or hot dog compressor. They are good for home or hobby use, during emergencies such as a punctured tire or even in construction sites.
Stationary compressors are quite powerful with large capacity and heavyweight. They are not meant to be transported from place to place. These are used in garages, workshops, or industries.
Consequently, these compressors are more expensive than portable ones. Besides, wheeled compressors fall somewhere in the middle. These are not as lightweight to hand-carry, but definitely far more portable than stationary ones.
Noise Level
Noise level can be an issue for many compressors, specially oil-free and portable ones. Of course, you would always like a quiet operation, especially for home use or indoor applications. However, as you can see, it is associate with many other factors such as lubrication, the number of moving parts, cost, etc.
There are some advanced technologies out there to reduce the noise level, e.g., dual-piston operation. Besides, you can also use enclosures, or sound-dampeners to cut down the noise.
Air Treatment
Appropriate air treatment is crucial for the performance and durability of an air compressor. Air treatment components include air dryers, air filters, etc. However, the main goals of air treatment are:
- Removing moisture and impurities
- Refining contaminants and preventing buildups
- Filtering or separating oil
Always make sure that the air delivered is clean and dry. Moist, dirty air can cause deteriorate the compressor functions and eventually damage it. Likewise, a lack of oil separator will pose a health hazard if the atomized oil contaminates the air you breathe.
Therefore, always make sure to opt for the proper air treatment measures for your compressor.
Installation
While small compressors for residential use are relatively easier to install, there are few key things you need to remember, such as-
- Install the compressor in a clean, dry, and well-ventilated area.
- Keep ample space between the compressor and your wall.
- Hose lengths and attachment fittings should be appropriate.
- Voltage should be compliant.
Installation of stationary or industrial-grade air compressors can be tricky, so you may need help from certified professionals.
Essential Accessories
Air compressor accessories and kits are indispensable to improve the performance of your air compressor. Some essential accessories include regulators, air hoses, gauges, tool attachments, etc. Besides, lubricators, additional tanks, replacement pumps, and extension cords are necessary for certain types of compressors.
Hence, carefully pick good-quality accessories to minimize the need for maintenance.
Air Tools
The ultimate purpose of most compressors is to power your air tool/s. There are various pneumatic tools such as nail guns, ratchets, air hammers, sprayers, and grinders. Each air tool has a specific requirement for airflow rate and pressure.
Typically, based on the highest CFM required, 50% is added as a margin of safety. For instance, for a spray gun of CFM 4 at 40 PSI, the CFM of the air compressor should be at least 4 x 1.5= 6 CFM. This chart can give you an idea of the CFM needed for specific air tools.
Perfect Compressor for Homeowners
Homeowners have specific needs while searching for a perfect air compressor, such as-
- Small size and capacity (usually 2-6 CFM) should be enough for most jobs.
- Portability or wheeled compressors are highly preferred.
- Quiet operation is desirable.
- Electric compressors are favorable to avoid fumes.
This article talks about some excellent portable compressor options for home use.
For a home garage or workshop, where you will use multiple pneumatic tools, a bigger sized compressor would work better. Check out this article for detailed guidelines about choosing the best compressor for your home garage.
Perfect Compressor for Construction
For the construction business, people usually go for a larger compressor, sometimes with additional portable compressors. These compressors should be reliable, durable, and suitable to run small air tools like nail guns.
Here are some suggestions about construction-grade twin stack as well as pancake air compressors.
Perfect Commercial Air Compressor
Commercial air compressors are quite expensive, so you should thoroughly think through different aspects before you invest. The price will vary depending on the size, airflow, and pressure you need for a particular use.
Usually, stationary compressors are preferable for commercial and industrial applications. Look no far and find here the five best air compressors that are perfect for commercial use.
Our goal has always been to provide you the best information available so that you can make your purchasing decision with confidence. With a thorough understanding of different air compressor criteria, we hope this buying guide will assist you in finding the air compressor best-suited for your need.
Summary
To recap, we discussed the main definitions and acronyms to know when researching air compressors. It’s important to know what you’re looking at and understand the terminology.
We discussed the different grades of machines out there, we discussed the pros and cons of stationary vs portable units, reviewed how to determine CFM needs, and finally reviewed tank size.
