If you are a mechanic or contractor and require an efficient air compressor to keep up with your professional needs, you have hit the right article. In this air compressor buying guide, we will inform you about the equipment’s essential features, how it works, what to look for before purchasing one, and the best of the lot to get your hands on.
But before that, let’s learn about certain fundamental ideas about the product from our quintessential air compressor buying guide of 2020.
What is an Air Compressor?
Air compressor is an equipment used to store air in a compressed form for later use. The air stored has potential energy, which you can release later to perform works such as power pneumatic tools, clean a surface, and fill tires.
Bellows used in ancient times are some of the earliest known air compressors in the history of pneumatic machines. Each region had a version of its own; some used handheld ones while others used foot-operated variants and were mainly used for blowing fire.
The first modern air compressor model to be invented for other purposes than fire management was in 1762, which produced around 14.5 pounds per square inch. The advent of metallurgy and better resources of the 1800s gave rise to more advanced air compressors. Since then, the equipment has seen years of evolution before taking its much-advanced form of the current time.
An air compressor can supply power until the air in it remains at high pressure. Once the pressure drops, you need to charge the air compressor before using it again. Based on the variety of air compressors, you use electricity or fuel to repressurize the air.
How Does an Air Compressor Work?
Before we discuss what to look for when buying an air compressor, let us understand how do air compressors work. The air compressor works by pushing air into a container and preventing it from getting out. As we shove more and more air inside the container, it is compressed and gets pressurized.
If you are wondering what does an air compressor do, here’s your answer. It uses a power source such as an electric or fuel operated pump to push the air inside the container. It has a valve at the mouth of the cylinder to prevent the air from escaping.
To use the air compressor for any work, we need to open the valve, and then the air rushes out of the cylinder. This air comes out with force to remove dust or tighten bolts, and do other tasks. There are two ways to achieve air compression- positive displacement and dynamic displacement and both the methods have multiple subcategories.
Although the outcomes of all the types are quite similar, the process to achieve them vary. Let’s have a look at how positive and dynamic displacements work.
Positive displacement air compressor forces air in a chamber, which decreases the volume to compress the air. It is an umbrella term that indicates numerous air compressors powered through positive air displacement.
The internal system may vary among different machines, but the method of providing power is the same in positive displacement air compressors. Some positive displacement air compressors are ideal for industrial workloads, while some work efficiently for private projects and hobbyists.
Three types of main air compressors that use positive displacements are- Rotary Screw, Rotary Vane, and Reciprocating/ Piston Type. We have talked about these air compressors in the upcoming parts of the article.
Dynamic displacement air compressors employ a rotating blade powered by an engine to generate the airflow. It then restricts the air to create pressure, and the compressor stores the kinetic energy within it.
Large projects like chemical plants, steel manufacturers use dynamic displacement air compressors; therefore, it is unlikely to find them around your local mechanical stores. Dynamic displacements, like the positive ones, have two variants- axial and centrifugal. We have talked about these in the upcoming sections.
Types of Air Compressors
When you buy an air compressor, you will need to consider various options to select the best product. Air compressors vary depending on the pressure delivery system, design and operation principle, power source, tank shape, and portability.
Types of Air Compressor Depending on Working Principle
All air compressors are not the same, depending on the usage; you might want an air compressor that works in a particular manner. You cannot use an air compressor used to tighten bolts to power a jet engine and vice-versa. So, here are the different types of air compressors based on their working principle.
Based on the Pressure Delivered
The first division we are considering is on the basis of pressure delivered by the air compressor. Air compressors force more and more air inside the storage tank to increase the pressure. The compressor shuts off when the storage tank’s pressure reaches its engineered upper limit. We can further divide air compressor into three types, such as-
Low-Pressure Air Compressors
We use low-pressure air compressors when we require a discharge air pressure of fewer than 150 PPI or 10 bars. Workshops, small machines, auto body repair shops, and small manufacturing shops use these durable and straightforward low-pressure air Compressors.
Medium-Pressure Air Compressor
We use medium-pressure air compressors when we require a discharge air pressure of fewer than 151 PPI to 1000 PPI or 10.5 to 69 bars. Various industries like briquette oxidation in petroleum industries, pharmaceutical factories, cement production use medium-pressure air compressors.
High-Pressure Air Compressors
We use high-pressure air compressors when requiring a discharge air pressure of greater than 1000 PPI or 69 bars. Industries and factories use these for energy storage and mechanical transportation work.
Other than that, the operation of pneumatic production equipment, air pipes, clean pressure cutters, and the transportation or cooling of components during production also use high-pressure air compression.
Based on the Design and Principle of Operation
Reciprocating Air Compressor
Reciprocating air compressor or piston compressor uses pistons controlled by a crankshaft to supply the gas at maximum pressure. This type of air compressors are mainly for the use of smaller worksites and not for continuous utilization. There are two primary subdivisions of reciprocating/ piston air compressors, namely-
Single-Stage Reciprocating Air Compressor
This type compresses the air on one side of the piston while the other part deals with the functionality of the air compressor. When the piston goes down, it draws in the air, and when it goes up, it compresses the air.
Single-stage reciprocating air compressors are comparatively affordable than other compressors, and you can find them in almost all mechanic shops.
Two-Stage Reciprocating Air Compressor
It has two compression chambers on both sides of the piston. There is a continuous stream of water through the engine, and the double-acting compressor cools water taking its aid. This system gives better cooling than any other air compressors.
Two-stage air compressors are better for workshops and large factories than small private projects as they are quite expensive. Both single-stage and double stage reciprocating air compressors are excellent in their own ways. We must say that two-stage compressors are better than single-stage compressors if we have to compare both types.
Double or two-stage air compressors are ideal for large factories and industries as they are ideal for working with high-pressure pumps. Therefore, large factories can’t rely on single-stage reciprocating air compressors.
Rotary-Screw Air compressor
A rotary screw air compressor is a gas air compressor that works with a rotary-type positive-displacement mechanism. It uses two helical screws, called rotors, to compress the air.
People commonly use rotary screws to replace piston compressors, which require large volumes of high-pressure air. These compressors are found either for large industrial applications like- chillers or in high-power air tools such as jackhammers and impact wrenches.
Rotary Vane Air compressor
These air compressors come with a rotor with multiple blades. The rotor is placed in the chamber in such a way that it is not in the center. When the motor rotates, the blades move in and out while maintaining contact with the cylinder walls. This rotation changes the volume of the chamber as the blades rotate and help compress the air.
Axial Air Compressor
An axial air compressor or a turbo air compressor is a dynamic rotating air compressor. It uses airfoils, which is an array of fan-like parts to compress the air. They are ideal for a situation where you need a high rate of flow in a limited volume.
Centrifugal Air compressor
Centrifugal air compressors are the largest air compressors. They rely on an impeller, a rotating disk, placed in a particularly shaped housing. This arrangement pushes the air to the impeller’s rim, thus increasing the airflow.
A diffuser, a kind of divergent duct, helps convert this kinetic energy into pressure energy. Refineries and chemical plants use these centrifugal air compressors primarily.
Based on Power Source
Based on Power Source
Compressing air requires energy that can be generated with the help of electricity or fuel. Here is a list of electric or gas-powered air compressors; let’s have a look at each type.
Electric Air Compressors
An electric air compressor drives the crankshaft with the help of an electric motor. These compressors offer high efficiency and are quiet, but the power output is lower than gas air compressors.
Gas Air Compressors
Gas air compressors rely on a fuel-powered engine to drive the crankshaft. As a result, you get sufficient power, but they make noise and have lower efficiency.
Based on Tank Shape
We can classify air compressors into four shapes, which are- pancake, twin tank, horizontal, and vertical. The only difference between these compressors is in terms of portability. However, twin tank air compressors offer more power than the other varieties.
Pancake Air Compressor
Pancake air compressors are a perfect choice if you want portability. They are inexpensive and useful for operating nail guns and cleaning.
Twin Tank Air Compressor
Twin tank air compressors are made for professionals who want more power and capacity. People use twin tank air compressors to drive power tools in workshops or at work sites.
Horizontal Air Compressor
Horizontal air compressors are useful if you want to work in a constricted space and don’t need to move the compressor.
Vertical Air Compressor
Vertical air compressors don’t differ much from horizontal air compressors, except for the orientation and space they take. They offer great portability as most of them come with wheels.
Based on Portability
Air compressors can be of two types depending on whether you want to use them in a fixed location or move them around the workplace.
Portable Air Compressors
As the name suggests, these air compressors are small enough, which you can easily carry to your work station/ worksite. You will find these air compressors in power tools such as jackhammers. They are not as effective as the bigger and more powerful variants.
Stationary Air Compressors
You’ll find these air compressors in chemical plants and refineries, and other places where large amounts of fluid are compressed. These compressors offer high compression power but are generally immovable or require special equipment for movement.
How to Use An Air Compressor?
You can use an air compressor for varied purposes. Most people get an air compressor for home garage. They use it for filling the air in tires or for cleaning. Some might even use it for airbrushing.
Professionals rely on an air compressor for tasks at their workshops or a building site. Air compressors are commonly used to power pneumatic tools.
What do You Use an Air Compressor for?
If you ask what is an air compressor used for, you will get different answers. However, you need to be careful about the specification of the air compressor. Below are some of the uses of an air compressor –
- Filing tires – As we have mentioned in the previous point, people use an air compressor for tires in their garage to pump up the flat tires. It is an absolute necessity for filling punctured or flat tires.
- Air Tools – You will need an air compressor for air tools like- impact wrench, chipping hammers, horizontal grinders, tire inflation, trenchless piercing tools, pneumatic saws, rock drills, etc. The manual labor is decreased in such working conditions to a considerable extent with air compressors’ help.
- Painting – Pneumatic air compressors like paint guns and sprays are great tools for painting. These air compressors for painting tools make the tedious painting task quick, easy, and much more fun.
Home Garage – Air compressors for home garage is a very convenient option nowadays. You can inflate or pump up the tires of your vehicle like your car or bike tires with its help.
Steps on How to Use Air Compressors
Here are the few steps you must follow for the best performance when using an air compressor.
- Ensure that your air compressor is lying on a flat and stable work surface.
- Check if the power switch is off, then connect the cord to a plug point (ensure proper grounding).
- Before turning on the air compressor, check if it has sufficient oil.
- Most piston-based air compressors have an oil level indicator near the motor.
- If the compressor doesn’t have enough oil, remove the cap and fill the oil to the marked level.
- Don’t skip the user manual of your air compressor as different brands might have different air compressor designs.
- The next step involves checking if the drain valve at the bottom part of the compressor is closed.
- Once you’re done with the checks, turn on your air compressor.
- Wait until the pressure gauge shows that the compressor has reached optimum pressure. In household compressors, the pressure range is around 110 to 120 PSI.
- Connect the air hose to your compressor and secure it firmly.
- You are all set to use the air compressor. Attach the tool you want to use and open the valve.
Note: Don’t forget to remove moisture from your air compressor after use. Take a look at the manual to know how frequently you need to do so.
How to Choose an Air Compressor?
Buying air compressors for the first time is a complicated task. As we have discussed earlier, there are multiple variants of the equipment, so you have to be sure of your requirements and buy the product accordingly. When you are getting an air compressor for the first time, you might ask what air compressor should I buy?
We have dedicated this section to solve your queries you might have regarding the purchase, and it will inform you how to buy an air compressor. Consider the given factors to get the best air compressor for your needs.
Analyze the Requirements
The first step of the process includes assessing your requirements. As mentioned before, there are different kinds of air compressors for various tasks. It would be useful to make a list of tasks that you plan to perform using an air compressor.
Doing this will help you see if a particular compressor is suitable for you to do your job or not. It would also prevent you from wasting money on a product that you don’t need.
Consider Tank Size
The tank size of an air compressor is also essential. You don’t want to wait for the compressor to charge again in the middle of your work. Identify the usage and buy an air compressor with a tank big enough to fit your needs.
The tank size of an air compressor is usually measured in gallons. If you are thinking about How many gallons air compressor do I need, you need to emphasize upon the usage of the equipment. For instance, if you want to purchase an air compressor for tasks such as nailing or stapling, you will require short bursts of air at intermittent durations.
In such a scenario, an air compressor with a small tank would be the best buy.
On the other hand, if you are planning to use your air compressor for heavy duty tasks such as grinding, air sanding, etc, you will need a larger tank.
A big and bulky air compressor wouldn’t be useful for occasional home use. Similarly, a pan air compressor would not be suitable at a construction site. Keeping your requirements in mind, you can opt for an air compressor with a small or large tank.
Consider the Power Source
Air compressors work either with fuel or electricity; depending on the location and use, you need to pick one. Generally, people who want to use air compressors at home or in a small workshop should get an electric air compressor. They are quiet and highly efficient.
However, if you intend to use the air compressor in a remote location or on a worksite, get an oil-powered air compressor. Oil compressors may be loud and bulky, but they offer the power needed to drive the power tools.
On the other hand, operating an air compressor can be troublesome if you work in environments with frequent power cuts or do not have proper outlets. In such cases, you can opt for mobile air compressors that operate on gasoline or diesel engines.
Such air compressors can also run by integrating them into the engine of a vehicle or by using other methods such as a hydraulic port.
Consider the performance ratings
We are going to look at a few different performance ratings usually found in air compressors, which are- SCFM, CFM, Horsepower, and PSI.
- SCFM: Standard cubic feet per minute is a specification that indicates the volume of air the air compressor may provide at a specific pressure.
- CFM: Cubic feet per minute is the amount of air taken into the compressor from outside. CFM varies depending on humidity, temperature, atmospheric pressure, etc.
- Horsepower: Horsepower is a measuring unit that calculates the amount of work an engine can perform.
- PSI: PSI or Pound per square inch measure pressure in air compressors. PSI and CFM together indicate the pressure and maximum air volume produced by an air compressor.
Determine the Size of Air Compressor
What Size Air Compressor Do I need? People who are buying an air compressor for the first time ask this question very often. Manufacturers offer air compressors in different sizes based on the maximum pressure that can be reached, safety, and the output. You need to check the CFM, Horsepower, PSI, and SCFM of the equipment while purchasing it.
Considering the power and capacity, people ask these questions when they choose an air compressor.
What Size Air Compressor do I Need to Fill Car Tires?
If you intend to fill car tires using an air compressor, you might want to get a 110 PSI air compressor (most car tires need a pressure around 30-35 PSI). A tank capacity of 5 to 6 liter would be sufficient. If you plan to fill an RV tire, you might need a bigger and more powerful compressor.
What Size Air Compressors do I Need for Air Tools?
Air-powered tools need pressures ranging from 90 PSI to 150 PSI. A medium air pressure compressor of around 110 liters would be perfect for most workshops. If you own a smaller workshop, get a smaller compressor.
What Size Air Compressors do I Need for Impact Wrench?
Most impact wrenches work at pressures between 90 PSI and 120 PSI. So, a low-pressure compressor with a capacity of 30 liters would be a convenient option.
What Size Air Compressor do I Need to Paint a Car?
Painting requires lots of compressed air at low pressure. So, if you plan to use an air compressor for painting, get one with at least 60-gallon capacity.
What is a Good Size Air Compressor for Spray Painting?
Depending upon the requirements, you need to use an air compressor that can produce pressures around 120 PSI. For small scale tasks, a 60-gallon tank would be sufficient. Larger jobs might require tanks with a capacity of more than 100 gallons. Sandblasting also requires a similar setup.
What Size Air Compressor for Framing Nailers?
Framing nailers require a short burst of high pressure to do their job. As a result, you can work with an air compressor capable of reaching 120 PSI with a capacity of 5 to 6 gallons. Similarly, you can use it for nail guns as well.
The size of the air compressors will vary for other applications like a nail gun, impact gun, sandblasting, blow out sprinkles, RV tire inflation, etc.
Portable Air Compressors vs. Stationary Air Compressors
If your work requires you to shift the air compressor around with you, such as cleaning and painting, a portable air compressor would be the right choice. You can use handheld compressors for minor tasks, whereas you need a bigger compressor with wheels to manage bigger jobs.
Air compressors used in turbines and factories need to produce a lot of pressure. As a result, these compressors are quite bulky and not easily portable. Unless you plan your work deals with oil refineries or chemical plants, you don’t need big and stationary air compressors.
Oil-filled Air Compressors vs. Oil-free Air Compressors
Typical air compressors use a piston to suck and compress air. These pistons require lubrication for smooth functioning. In oil-filled air compressors, you need to add oil to ensure that the piston works properly. These compressors are heavy, but they work longer and provide hassle-free maintenance.
In oil-free air compressors, the piston and the walls are coated with Teflon or similar material for smoothening the motion. As these compressors don’t need oil, they are lightweight. However, you need to seek professional help if the piston is unable to move freely.
How much do Air Compressors Cost?
Here you need to explain in 2-3 paragraphs about the cost of an air compressor as per three major grades as like in the source. Air compressors come in multiple shapes and sizes and work on different principles. Due to these differences, the price of air compressors varies a lot.
Consumer Grade Air Compressors
These are the most affordable air compressors on the market and are made for use at homes, offices, or small workshops. The cost varies between $15 and $2400. You can get a 2.5 HP electric compressor with a 5-gallon tank for $500. A slightly bigger gas air compressor, 8 gallons, would cost you $900.
Contractor Grade Air Compressors
As the tank’s size increases to more than 20 gallons, you enter the contractor level air compressors. These compressors would set you back anywhere between $200 and $5400. A 7.5 HP, 80-gallon electric compressor will cost around $2000.
Commercial Grade Air Compressors
Finally, we have commercial grade air compressors. Industries and factories use these large compressors, which cost more than $10,000.
Air Compressor Safety Tips
Working with tools such as air compressors requires you to be extra careful. The compressor stores air at high pressure and people use it to operate power tools such as nail guns. Due to this reason, you need to take these safety measures to avoid any mishap.
Also, refer to your air compressor’s user manual to know what additional safety measures you need to take while operating the equipment.
Use Gloves and Goggles
Whenever you are at your workplace, put on goggles and gloves for additional safety, small things, such as screws and wood chips, could fly while using the air compressor and get into your eyes or hit your hands.
Check for Leaks or Other Defects
Before you start working with your air compressor, check it for any leaks. If you use an air compressor daily, check it for leaks every day. A slight leak can lead to an explosion or fire if left unchecked. Many people think that it is only the gas-operated compressors that can cause a fire. However, electric compressors can also lead to a blazing inferno due to a short circuit.
It is better to spend a few extra minutes to ensure that the equipment is safe to use than ignoring it, leading to an accident.
Keep the Compressor Outside
Irrespective of the fact that your compressor is gas-operated or electric keep it outside of your workplace. Air compressors, especially gas-based, release toxic fumes while they are working. Gases such as carbon monoxide can be fatal if inhaled for extended durations.
If you are working in a small workshop, never keep the air compressor inside it. On the other hand, big workshops with proper ventilation systems could keep their air compressors inside; however, experts advise not to do so.
Servicing Your Air Compressor
Using an air compressor regularly leads to wear and tear. If you don’t fix these minor issues, they might become severe and lead to catastrophic consequences.
If you use an air compressor that requires oil for lubrication, you need to take care of that as well. Most air compressors, especially rotary screw compressors, use synthetic oil. These compressors require an oil change after 6000 to 8000 hours of use. Use an SAE 30 weight oil in operating temperatures ranging between 34° F and 100° F. Use SAE 20 weight oil for colder conditions.
Consult the manual to know more about lubricating your air compressor. If you refer to the manual for your air compressors, you will get to know how to take care of your equipment and how frequently you should service it. Consult a professional if you are unsure how to service your air compressor.
You should also ensure to place the compressor on a stable and plane surface. When operating an electric compressor, provide a steady voltage supply. In the case of a gas-powered compressor, check if it has proper ventilation.
Shopping by Brands
When you search for the best air compressors, you will come across multiple products from different brands. To help reduce the burden of choosing the best equipment, here are the five best air compressors in 2020.
Bostitch BTFP02012 is one of the top pancake air compressors. Its lightweight and compact size make it ideal for personal use. It has six gallons capacity and can supply pressures up to 150 PSI. This oil-free air compressor produces little noise and is perfect for operating nail guns and cleaning. It weighs 31 pounds and measures 17 x 17 x 19.25 inches.
- Lightweight and easy to carry.
- It requires minimal maintenance.
- It is perfect for homes and small workshops.
California Air Tools 10020C
California Air Tools 10020C is an oil-free compressor with a 10-gallon capacity. Its small size and low noise level make it perfect for use around your home. It is capable of generating pressures up to 125 PSI and weighs 82 pounds. It comes with wheels which allow you to move it quickly. You can keep it running from anywhere between 30 minutes to 1 hour on a single charge, making it suitable for small scale spray painting.
- It is easy to maintain and operate.
- The compressor creates very little noise.
- It is perfect for operating small power tools.
Makita MAC700 Air Compressor
Makita MAC700 air compressor is ideal for professional use. It is an oil-lubricated compressor that allows you to run it regularly without extensive maintenance. The compressor weighs 60 pounds and is quite portable. It can produce pressures up to 130 PSI. It has a small 2.6-gallon tank. However, the tank is insufficient to operate power tools for extended durations.
- It is lightweight and portable.
- The maintenance process is easy.
- Usable for extended durations with little wear and tear.
This pancake-style air compressor from Dewalt has a capacity of 6 gallons and can produce pressures up to 165 PSI. As an oil-free compressor, it doesn’t require any maintenance. This compressor will be a great option if you want an affordable and lightweight compressor to use in homes and small workshops.
- It produces very little noise.
- Lightweight and portable.
- Oil-free design means little to no maintenance.
Porter-Cable C2002 is a great air compressor for use in homes and offices. It has a 6-gallon capacity and can produce pressures up to 150 PSI.
The high-pressure design is capable of driving most power tools, making this compressor useful at worksites. It weighs 30 pounds and requires little to no maintenance.
- It is easy to operate.
- The compressor is lightweight and portable.
- It is affordable.
As you can see, air compressors are not as simple as they seem. Without having a proper understanding of how they work and which ones are suitable for a specific task, it would be difficult to choose the correct equipment.
After going through this guide, you would have sufficient information to help you choose the best air compressor. You can select an air compressor that suits your needs by following our informational guide or pick one mentioned in our list.