The Complete Air Compressor Buying Guide

Posted on: September 21, 2021

Air compressors make tough jobs more manageable, continuously turning the surrounding air into a useable power source. Each year, we discover more uses for compressed air, and our air compressor technology has rapidly evolved to keep up with these constantly changing needs. An air compressor can have immediate impacts on your time and energy, saving you immensely when you know which air compressor to buy.

If you need to determine the best selection for your unique needs, our comprehensive air compressor buyer guide will inform you on what to look for in an air compressor. We’ll help you choose an air compressor that’s right for the job.

Types of Air Compressors

All compressors work by using a mechanical component to increase the air pressure and reduce the volume of trapped air. The duty cycle is complete in most models once the maximum air pressure is reached inside the tank.

When choosing an air compressor, it helps to know the basic mechanics of each available option so you can make a more informed purchase.

Rotary Screw

In a rotary screw compressor, the mechanical component used to reduce the volume is a pair of screws. These twin spiral screws are meshed together, turning continuously to maximize air intake and air payout. Rotary screw compressors use a positive displacement compression system — air fills the sealed chamber where it is squeezed between the two helically opposed rotating screws. The trapped air is compressed to a proper pressure level for use in various applications.

Rotary screw compressors were explicitly introduced for prolonged heavy-duty and high-precision situations. They are durable and reliable, with extremely high air flow rates, impressive horsepower and fewer moving parts. Most models are oil-flooded, but rotary screw units ensure safe operation even at extreme temperatures. Rotary screw air compressors require less maintenance over time and can undergo high-power applications for extended periods. The continuous airflow and pressurization are particularly valuable for the automobile industry.

Reciprocating/Piston

Reciprocating air compressors are the most widely used positive-displacement compressor — popular for agricultural, automotive, gas processing, refrigeration, general manufacturing and many other applications.

They operate using a crankshaft-driven piston inside of a cylinder. The internal crankshaft drives the piston in a back-and-forth motion to reduce the volume of air. As the piston retracts, the surrounding air fills the cylinder’s upper portion. When the piston extends, compressed air is pushed into the tank. As the volume of trapped air decreases, the pressure builds to a proper level.

The air intake method remains the same whether the unit uses a single-stage or two-stage air compression process. Piston air compressors can produce high power at low energy levels. Its compact design makes the reciprocating air compressor easy to transport and less likely to need repairs.

Despite having fewer moving parts, the piston air compressor produces more heat and noise than other types when the internal components touch. Thankfully, most reciprocating air compressors are best used intermittently and don’t need to run continuously. Oil-less compressors can also reduce the overheating and noise associated with standard piston air compressors.

Scroll

Scroll air compressors use two spiral-shaped circular scrolls to reduce the air volume. One scroll is fixed in place at the compressor’s center, while the other fits inside this stationary scroll and moves in a fast circular motion. Compared to different air compressors, a scroll unit has fewer moving parts and significantly reduced vibrations. The standard model was initially designed for longevity — a factor that’s still favored today.

Scroll compressors can operate at various intensity levels and cover a wide array of industrial air compression needs, including automotive, electronics manufacturing and refrigeration plants. They produce the cleanest air according to IOS industry standards. While some models may require lubrication, especially if they produce higher pressure, many standard scroll compressors feature an oil-free design. Oil-free scroll systems make less noise than other types and are ideal for the pharmaceutical, dental and food industries.

Portable vs. Stationary

Air compressors can either have a portable model designed for quick mobility or a stationary model intended for use in one location. Larger models are often fixed and can store a greater volume of air. Meanwhile, portable air compressors feature a smaller, lighter design that can keep tools powered from anywhere around the house or job site — even on a roof or in a crawl space.

Portability allows these air compressors to support various lifestyles. Models that feature a smaller storage tank are ideal for home and light industrial use since they can quickly move through the work area with ready-to-use compressed air. Portable compressors have handles or wheels that allow them to go exactly where they’re needed.

Most portable models have a single-stage piston design and electric motor. Common styles of portable air compressors include:

  • Pancake: Round, flat storage tanks are mounted on the bottom of the unit for added stability and space-saving design.
  • Hot-dog: This style features a horizontal design with a single, cylindrical tank.
  • Twin-stack: Two horizontal, cylindrical tanks are stacked for added air capacity without increasing the necessary floor space.
  • Wheelbarrow: These units have a wheel and handles to move the twin cylindrical tanks where they’re needed.

You can easily carry hot-dog and twin-stack compressors around the house for use in different areas. Truck-mounted and wheelbarrow designs are beneficial on construction sites. Choose from several styles of both portable and stationary air compressors to ensure you make a worthwhile investment.

Oil-Flooded vs. Oil-Free

Depending on the specific applications, it can be crucial to know how lubrication works in an air compressor. The two categories of oil pumps could significantly impact your buying decision:

  • Oil-flooded: These air compressors use oil to lubricate the walls and bearings with occasional splashes. Oil-lubricated systems typically have a more durable design, though they also tend to produce more heat and noise as a result.
  • Oil-free: The pump receives unique lasting lubrication to ensure oil can’t contaminate the compressed air. Due to their enclosures, oil-free reciprocating compressors also benefit from reduced overheating and exceptionally low noise.

The piston ring used in oil-flooded piston compressors helps form a seal inside the combustion chamber, minimizing the risk of oil contamination. Other prevention methods, like oil separators and air-line filters, can also keep oil from entering the tank. However, oil-flooded models will always risk oil seepage. Specific industries must ensure 100% oil-free air. Even small quantities of contamination can cause costly product losses and production downtime depending on the application.

Oil-free air compressors are designed for clean environments where it is essential to eliminate all oil contamination risks. Because oil-free air compressors are quiet and low maintenance, they can run all day without stopping or slowing down. Oil-free compressors are ideal for around-the-clock operations and applications in the following industries:

  • Food and beverage processing
  • Pharmaceuticals manufacturing
  • Fermentation
  • Wastewater treatment
  • Electronics manufacturing
  • Chemical and petrochemical processing
  • Textile production

Newer air compressor technology removes oil from the lubrication process entirely so you can ensure the air used in your process or product is 100% oil-free. Other technologies like variable speed drive (VSD), variable frequency drive (VFD_ and two-stage piston designs can help oil-flooded compressors have a quieter operation, too.

Two-Stage vs. Single-Stage

Reciprocating air compressors are the most widely used type of positive-displacement compressor. They rely on a piston inside a cylinder to compress air and use either a single piston and cylinder to operate or a two-stage process. Standard units for home use are typically single-stage models with one piston cylinder. Two-stage piston compressors maximize the strength of two cylinders instead.

Single-stage reciprocating compressors work by filling the cylinder with air and compressing it in a single piston stroke. These units are best for lower pressure applications since the air is generally compressed to a pressure of approximately 120 PSI. The most common air compressor models for home use are single-stage. They are best used to serve intermittent, light-duty jobs around the house, having limited efficiency and capacity for applications that require a higher pressure of air.

Two-stage piston compressors have two piston cylinders, each with a different diameter. They use the same air intake method as single-stage machines, but the air is compressed through two chambers instead of one. The second, smaller chamber ensures the air is pressurized to the required extent. Most two-stage units reach a higher pressure of approximately 175 PSI. The additional cylinder stage allows these compressors to work more effectively and run more air tools at once.

The higher cost of two-stage units may influence your air compressor choice. While they offer more reliability for demanding, continuous use applications, it is important to consider whether you will make effective use of the two-stage compressor’s higher pressure. Avoid overspending on features and capabilities you’re unable to utilize.

Air Compressor Power Sources

An air compressor typically consists of a power source, an inlet, a discharge valve, a pump and a storage tank. The inlet draws in surrounding air and the discharge valve releases pressurized air for use. Meanwhile, the pump helps compress the air. Air compressors are usually powered by either an electric or gas motor.

Electric-powered compressors are the most common designs for use in enclosed spaces. They work in any dry area with access to a stable electrical supply. Electric units are quieter and require less maintenance than other models. Portable electric compressors have limited mobility, however. Many consumer-grade air compressors can function on a 120-volt household current. Ensure your electrical supply can handle a specific model’s requirements before buying.

Gasoline-powered compressors are typically used for outdoor work areas where electricity is limited or unavailable. Gas fumes can make these models unacceptable for enclosed spaces, so it is vital to maintain good air quality while it’s in use. Air compressors powered with gas generally have more horsepower.

Air Compressor Specifications

Familiarize yourself with helpful air compressor terms to help ensure you get the best unit for your needs:

  • Horsepower and pounds per square inch: The horsepower (HP) rating indicates the power a motor produces. Higher horsepower means the air compressor can create greater air pressure, measured in pounds per square inch (PSI). For many single-stage compressors, the pressure limit is 125 PSI. Air compressors with a higher PSI can compress a larger air volume, allowing for longer use of air tools. The pressure switch goes off to complete the duty cycle when the maximum air pressure is reached in the tank.
  • Cubic feet per minute: Cubic feet per minute (CFM) describes the volume of air a machine compresses at specific PSI levels. CFM ratings increase as you lower PSI outputs. Determine the required CFM rating of your air tools and choose a compressor that exceeds this requirement. An added 50% to the required CFM is a reasonable margin of safety.
  • Average CFM: Air tools are often rated based on a 25% duty cycle for intermittent use known as average CFM. This rating can be challenging for tools used continuously. The average CFM is acceptable for occasional usage, but continuous use applications need extra calculations to determine the required CFM rating. If you want to use an air tool continuously, consider multiplying the average CFM by four to determine the continuous CFM rating.
  • Actual CFM: Air compressor manufacturers use actual cubic feet per minute (ACFM) to describe the actual volume of air compressed in one minute under standard conditions. Rated operating conditions for speed, temperature and pressures are considered in the calculation.
  • Tank size: Most manufacturers rate storage tank size in gallons. Smaller tanks typically store around four to six gallons, with larger tanks storing more pressurized air at higher volumes.

 

Air Compressor Features

Additional features allow homeowners and businesses to choose air compressor designs that can support any lifestyle or industry. Determine what features you might require to get work done safely and efficiently:

  • Oil-free pumps reduce maintenance and eliminate the risk of oil contaminating the compressed air.
  • Belt-driven systems generally have a longer life, provide quieter operation and limit heat transfer from the motor to the pump.
  • Low-oil shutdown prevents unnecessary downtime and costly repairs when oil levels are low.
  • Thermal protection stops the motor automatically when it senses an electrical problem like the overloads heating up.
  • Air-cooling systems ensure the pumping machinery remains cool throughout the process.
  • Adjustable exhaust ports allow the user to direct exhaust away from the work area.
  • Multiple couplers allow the unit to handle various tasks without needing to connect and disconnect tools.
  • A roll cage protects the air compressor from severe on-site damages and accidents.
  • Added accessories and tools like air hoses, inflation components and nail guns increase the value of your investment.
  • Auxiliary air tanks increase the storage capacity for compressed air.

Air compressors with constant speed operation run 100% of the time. Meanwhile, auto start/stop operation stops and starts the airflow at preset pressures or as needed. Your air compressor may utilize one method or dual control compressors that offer both.

When an air compressor is certified by the American Society of Mechanical Engineers (ASME), it has met all the standards and manufacturing requirements. Look for an ASME certification label on the unit’s tank, which will indicate the use of high-quality materials and craftsmanship.

Uses for Air Compressors

When choosing a new air compressor, consider the various uses and types of air tools you’ll want to power. If inflating objects like tires, sports equipment and pool toys will be the primary use, a standard inflator or consumer-grade air compressor should provide suitable pressurized air.

Air compressors are used to power versatile air tools and machines, each with specific requirements for air pressure and volume. Standard air-powered tools include:

  • Nail and staple guns
  • Impact wrenches
  • Paint sprayers
  • Ratchets
  • Air hammers and chisels
  • Rotary tools and grinders
  • Sanders
  • Drills

You will need to determine the required CFM rating of each air tool you want to use before choosing an air compressor. Consider which air tools you’ll need to power and ensure your new air compressor has the necessary CFM and PSI rates.

Questions to Ask Before Buying an Air Compressor

The vast number of air compressor makes and models can be overwhelming for any buyer. When you fully consider its intended use, you make a more informed air compressor selection and significantly improve operations.

Start by answering three essential questions before delving into the finer details of your next compressor.

How Will You Use the Air Compressor?

Air compressors are used for a wide array of applications that can help determine the correct compressor type. Consider whether you need an air compressor for intermittent use or continuous use applications. Rotary screw models offer constant airflow and pressurization, while reciprocating air compressors work best when used intermittently.

What tools do you plan to use with your compressor? All air tools have an average CFM rating. Select an air compressor that can provide the power required for each tool you want to use. It is also crucial to determine how many devices will be used at once. Most single-stage models are intended to handle one-person operating tools. Two-stage piston compressors can efficiently power multiple tools simultaneously for intermittent use applications.

Where Will You Use the Air Compressor?

Decide how vital portability is to your daily operations. If you require a dependable unit that moves easily around the home or work area, you’ll want a mobile air compressor with wheels or handles for easy transport. Wheeled designs are beneficial when traveling to and from job sites. Larger, stationary models provide more outstanding performance and more power, so it may not be in the best interest of every industry to prioritize portability.

Do you have access to a stable electrical supply? This answer will determine which type of power source you require. Electric air compressors produce a more reliable source of power, while gas motors are more convenient for mobile air compressors and outdoor applications. Remember that you can utilize longer air hoses if the stationary electrical unit doesn’t reach your work area.

What Air Compressor Specifications Do You Need?

The most important metric — whether it’s air generation, storage capacity, workload or technology — could impact your final purchase. The maximum operating pressure, or PSI rating, will ensure air is compressed to the optimal pressure. Manufacturers measure the capacity of the tank in gallons, while the desired workload is based on the rated horsepower and air volume in CFM.

Air Compressor Applications

Compressed air has a multitude of uses both at home and in businesses. With new applications discovered every year, air compressors can help virtually anyone complete work efficiently and reliably.

Widen your knowledge about the various uses for air compressors and determine how to make the most of your investment. Different applications for homeowners, contractors and manufacturers call for different types of air compressors.

Air Compressors for Homeowners

Save on basic repairs and finish projects more efficiently when you know how to choose an air compressor for home use. Dramatically decrease project run times, whether you’re working with wood, precision painting, powering outdoor equipment or fixing a personal vehicle.

Air tools are versatile, safer and more powerful than traditional electric tools, making them an excellent investment for people looking to improve the value of their homes. Standard air tools like nail guns, drills and impact wrenches generally require 5 or less CFM at 70-90 PSI, while air sanders and large shears could require up to 10 or more CFM at 100-120 PSI.

Many homeowners want consumer-grade air compressors that handle all of the air tools they require. Most consumer-grade models can address needs below 7 CFM and 135 PSI, though it’s still crucial to ensure the compressor you purchase can drive the necessary air tools.

Inflators are the smallest air compressors, primarily due to the lack of a storage tank. For an inflator to supply compressed air, the motor must run continuously during the project. They are typically used for small household needs like inflating pool floats, tires and sports equipment. Most inflators have the power to drive staple guns or other air tools with small CFM and PSI rates.

The reciprocating air compressor is the most common type used in homes and workshops. The best air compressors for homeowners are typically smaller, portable models that can be hand-carried or wheeled quickly around the premises. They are more compact than stationary models, allowing homeowners to work in difficult-to-reach or tightly enclosed spaces. Larger single-stage piston compressors may work better for specific needs — the larger tank and increased power mean more capability for your home or workshop.

Consider upgrading to a professional-grade model if you want to complete advanced home-improvement projects on your own.

Air Compressors for Contractors

When it comes to contractor jobs, professional-grade air compressors provide more power and higher pressurized air for longer periods. These durable air compressors are designed to handle more demanding applications, using the pressurized air more efficiently than other models. Professional-grade units can withstand the rigors of any job site, saving you money with more capability to complete work at greater energy levels and longer run times.

For example, rotary screw compressors and two-stage reciprocating units can effectively run several air tools at once for regular, intermittent use applications. The most common application for contractors is to drive the necessary air-powered tools. Air compressors are often used in small and medium-sized businesses to power many different air tools and machines for various industries, including:

  • Numerous air tools for automotive repair
  • Paint sprayers for use in an auto body shop
  • Sanders in an auto body shop or woodworking
  • Pneumatic nail guns for roofing
  • Air drills and hammers on construction sites
  • Specialized machines for dental and medical services
  • Sandblasters in manufacturing facilities

The best type of air compressors for contractors are designed to be durable and portable. For contractors, portability can either mean carrying or wheeling the air compressor around the job site. Consider mounting a mobile air compressor to your truck or wheelbarrow, especially for applications in the construction industry.

Air Compressors for Manufacturers

Manufacturers who know how to choose an industrial air compressor can maximize their efficiency with improved safety and performance. Because manufacturing industries need reliability, industrial-sized air compressors are designed to provide steady airflow and keep production moving for a more extended period.

Many commercial and industrial-grade air compressors are stationary models with large storage tanks, greater horsepower, more CFM and more PSI. The air tank typically holds up to 120 gallons, allowing for longer run times and more capability to take on demanding applications. Machines with ASME certification indicate the use of high-quality components and advanced technology. Manufacturers should look for ASME-certified units to ensure efficient and reliable performance.

Satisfy various demanding industrial compressed air applications with the best types of air compressors for each industry. For some industries, compressed air is the only option to provide a safer and more reliable power source.

Both our reciprocating air compressors and rotary screw models feature significant benefits for a wide array of industries, including:

  • Agriculture and farming: Air compressors are an affordable and dependable solution for maintaining a successful farm. Many agricultural machines require compressed air, including water pumps, crop sprayers, pneumatic handling material machines, dairy machines and tractors. Compressed air is also used to supply greenhouses with proper ventilation and power conveyors that quickly transport grain to and from silos.
  • Manufacturing: Applications for compressed air have been discovered in nearly all fields of the manufacturing industry. Whether in refineries, assembly plants, plastics, transportation, metal fabrication or general manufacturing, many day-to-day processes require an intermittent or continuous stream of pressurized air. Industrial-sized air compressors offer the ideal solution to industries in high demand for a safe and efficient power source.
  • Automotive: Auto assembly plants and body shops require compressed air to power essential tools and operations. From vehicle assembly to engine construction and from cleaning to precision painting, air compressors are vital to every stage along the production line.
  • Mining: The rapidly growing need for air compressors first began with the mining and metal fabrication industry. Air compressors provide an invaluable source of reliable energy. Drive various pneumatic tools and safety equipment used in drilling, mineral extraction, material handling and transportation. Compressed air can even maintain the complex ventilation systems needed for underground mining operations.
  • Plastics: For the plastics industry to continue thriving, it requires a consistent power source that can deliver high-quality plastics for various products and applications. Consistently have the power to perform multiple delicate operations specific to plastics manufacturing, like blow molding and injection. Air compressors absorb fluctuations in the electrical current to provide unwavering power to the necessary equipment.
  • Aerospace: Manufacturers and designers of aerospace components use compressed air systems to ensure consistent quality control. Air compressors produce reliable power throughout all stages of production, from the assembly line to the final painting. Oil-free models are ideal for manufacturing specific aerospace components. They eliminate contamination risks that could harm the product or process.
  • Amusement parks: Air compressors keep operations fast and dependable so visitors can experience the fun reassured in the safety of amusement park attractions. Roller coasters and other rides rely on compressed air for hydraulic launch systems, brakes, power gates and other critical features. Improved maintenance operations like air compressor-powered washers make cleaning attractions quick and efficient.

Industries creating edible or consumed goods have strict requirements for their air compressors:

  • Food and beverage: To run their constant operations, the food and beverage industry requires consistent compressed air. The air must remain clean, dry and contaminate-free throughout the entire supply chain, and oil-free models help meet these requirements. Air compressors serve various applications, including packaging, mixing foods, filling foods and molds, powering air knives and nitrogen generation.
  • Brewing: All types of breweries can use compressed air for various craft brewing and distilling tasks. Reciprocating air compressors work best for keg washing and other low-pressure applications, while heavier-duty rotary screw models can help to drive assembly line processes.
  • Pharmaceutical: From mixing ingredients to bottling liquid and pill products, the pharmaceutical industry is highly regulated throughout every step of the formula’s creation. Compressed air systems ensure the equipment operation and medicine production are running at maximum efficiency. Air compressor-powered equipment maintains pressure in mixing tanks, bottle the finished formulas and assist in other jobs where consistency is essential.

Various sectors of the energy industry utilize air compressors:

  • Energy exploration: An air compressor can deliver reliable power to the energy industry for drilling rigs, petroleum refineries and pipeline operations. Air compressors are ideal for both onshore and offshore energy exploration since they provide consistent, efficient performance without concern for the turbulence and harsh conditions faced every day.
  • Oil and gas: Both large and small-scale oil and gas applications utilize compressed air systems. The most common operations include maintaining the pressure of processed gas during pipeline transportation and increasing the pressure during petroleum refinement. Pressurized air is also used in the manufacturing process for the synthesis of various petrochemicals.

Clothing-related industries use air compressors, as well:

  • Textiles: Air compressors help drive necessary tools and applications throughout the entire supply chain. To keep up with demand, many textile facilities use compressed air systems for fast and effective production. The pressurized air can consistently power spinning machines, air-jet looms, ginning mills and other equipment unique to the textile industry.
  • Dry cleaning: When it comes to the quality cleaning of garments, compressed air is typically used to operate dry cleaning presses, steam cleaners and chemical cleaning guns. The ideal air compressor for dry cleaning applications requires an average of 3 CFM at 70 to 90 PSI. Access to reliable compressed air allows you to focus on serving the customer with greater confidence in the performance of your equipment.

Home improvement and construction industries also make use of air compressors:

  • Plumbing: Truck-mounted and hand-carried air compressors enable plumbers to take compressed air with them to various on-site jobs. Some plumbers invest in a stationary model for their shop with a larger capacity and more power. Air compressors for plumbing typically have an electric motor and a v-belt or direct drive.
  • Painting: Paint sprayers are commonly used to speed up tedious painting tasks, especially for the construction and automotive industries. The right air compressor will ensure consistent pressure and volume for highly specialized jobs. Consider the control method needed and decide whether continuous speed or auto start/stop operation will work best.
  • Woodworking: Many woodworking and lumbering processes require air compressors for better quality control and safer working conditions. Manufacturers need reliable, high-pressure air to conduct spark-free operations. Air compressors can handle both the detail-oriented needs of furniture craftsmanship and the high-production needs of lumber processing.
  • Climate control: Air compressors designed for climate control must live up to the demanding market. Custom performance and diverse operating capabilities ensure quality climate control in various environments. The compressed air helps HVAC systems produce clean, dry air with minimal oil contamination.

Choose the Right Air Compressor With Quincy Compressor

As new advances in air compressor technology arise, the expectations surrounding your industry’s products and operations may also change. Stay on top of these developments with the legendary performance and reliability of Quincy products. Our air compressor products are backed by a dependable network of knowledgeable air experts who can guide you through the air compressor selection process.

Quincy Compressor has been a trusted name in the compressed air system market for over a century. For professional advice and support, contact Quincy Compressor today. Take advantage of our 24-hour service and locate an authorized Quincy Compressor dealer near you.