Whether you are inflating a tire or you do handy work around the house, an air compressor is a tool that you are definitely going to want to have on hand. In the simplest terms, an air compressor converts power from either an electric motor or a diesel or gasoline engine into potential energy, which is stored in pressurized air. The air compressor forces air into a storage tank, which increases the pressure, and when the pressure in the storage tank reaches its highest limit, the air compressor turns off and the air that has been compressed is stored in the tank, where it can be used for various applications, including inflating a tire, operating tools and machinery and even for spray painting.
If you are on the market for an air compressor, you are going to find that there are a lot of options available, which can make finding the best air compressor for your needs a bit of a daunting task. To help make your shopping experience as easy as possible and to help you select the best air compressor for your specific needs, we have assembled this hand buyer’s guide for you.
Types of Air Compressors
There are three main types of air compressors:
- Reciprocating air compressors
- Rotary screw air compressors
- Rotary centrifugal air compressors
Reciprocating Air Compressors
Reciprocating air compressors are positive displacement machines; in other words, they increase the pressure of the air by reducing its volume. They take in successive volumes of air, which is then confined in an enclosed space in which the air is elevated to a higher pressure. The reciprocating air compressor uses a piston with a cylinder as the compressing and displacing element. There are two types of reciprocating air compressors:
- Single stage – typically used for pressures that range between 70 psig and 100 psig
- Two stage – typically used for higher pressures ranging between 100 psig and 250 psig
Rotary Screw Compressors
This type of air compressor is a positive displacement compressor. They are simple to operate and maintain and are noted for their ability to provide a continuous compressed air supply. The cooling of the air that these compressors take in occurs inside the compressor, which means that the working parts are never exposed to extreme operating temperatures. Capacity control is accomplished via variable speed and variable compressor displacement.
Centrifugal Air Compressor
These air compressors rely on the transfer of energy from a rotating impeller to the air. They produce high pressure discharge by converting angular momentum, which is imparted via the rotating impeller. As such, these air compressors rotate at higher speeds than other types of air compressors. A centrifugal air compressor is ideal for use in situations that demand a continuous supply of compressed air and when output needs start at around 100 hp.
Air Pressure Considerations
There are several factors that should be taken into consideration when purchasing an air compressor. These factors include how you will be using the tool, how often, your space requirements, portability and cost, among other things.
One of the most important factors that should be taken into consideration when purchasing an air compressor is the rate of air flow. Air flow is measured by cubic feet per minute, or CFM, or by pounds per square inch, or PSI. When deciding on the type of air flow you need, you should consider how you plan on using the air compressor. For instance, if you plan on using it primarily for home improvement projects, you likely will not need more than 6.0 CFM or 90 PSI, but keep in mind that it is always a safer bet to go with the higher number.
Horsepower refers to the strength of the engine that drives the compressor. Air compressors offer a specific horsepower, and you should purchase one that offers a horsepower that meets your specific needs. Do keep in mind that CFM / PSI is more important than horsepower.
Air compressors are typically electric or gas powered. You should consider which type of motor is more practical for you in terms of the cost of operating the air compressor, as well as where you intend on using it the most. For example, if you don’t want to be tied to having access to an electrical outlet, you may want to opt for a gas powered motor; however, if the cost of fuel is a factor, an electric air compressor may be a better option for you.
Oil Free or Lubricated
If you are looking for an air compressor that operates at a low volume, a lubricated compressor is the better choice, as they tend to run much quieter than oil free models. Lubricate air compressors also tend to last longer. On the downside, lubricated compressors do tend to spray oil when they are used, which can be messy, and they will also need an oil change every now and again. If you want to use your compressor without the risk of having oil spraying about, which is particularly important in applications that require a clean environment, such as pressure cleaning or painting, than an oil free compressor is a better option.
Air compressors can range in size from compact to large. Consider what type of space you have when determining what size air compressor will better suit your needs.
If you plan on using your air compressor in different areas, you should opt for one that is easy to move about. Look for one that is lightweight and features a wheel and a handle, which will make it easier to move about.
Air compressors can vary significantly in price. The larger and more powerful the compressor, the more expensive it will be. Make sure you know how much you can comfortably spend before you start shopping so you don’t overextend your budget.
Air Compressor Features
Air compressors boast certain features that you may or may not find advantageous. The more features it offers, the more expensive it will tend to be, so you want to make sure that you know what type of features will work for you so that you don’t spend unnecessary money.
Inline Water Filers
An inline water filter is a feature that will remove the moisture out of the air before the air goes is put out to the tool you are using to power with the air compressor. If you plan on using your air compressor with pneumatic tools, this is an important feature, as moisture can rust or corrode the components of the tools.
Dual Air Line Hook Up
If you want to use two air lines, you will want to look for an air compressor that offers a dual line hook up. This feature is usually found on air compressors that offer a minimum of 175 PIS or 16 CFM of air.
Air Cooling System
This feature will cool the pumping machinery of the air compressor, which helps to extend its life expectancy.
Thermal Overload Switch
A thermal overload switch allows the air compressor to automatically shut off the motor if it happens to overheat, thereby increasing the life expectancy of the air compressor and saving you money.
An ASME Certification indicates that an air compressor is made of high quality materials and expert craftsmanship. If the compressor is ASME Certified, it will be marked on the back of the tank.
A roll cage helps to protect the air compressor from being crushes or battered while on the job site, which is a particularly useful feature if you are going to be using it in areas where it could potentially be exposed to hazardous conditions.
If you want to ensure your satisfaction, look for an air compressor that features a warranty. Should anything happen to the air compressor or you are not satisfied with the tool for any reason during the term of the warranty, you will be able to have it replaced, which can provide you with increased peace of mind.
Best Air Compressor Brands
There are several manufacturers that make air compressors, but how do you know which manufacturer makes the best product for your needs? To help you choose the best brand, we tested air compressors from various manufacturers and did some in-depth research. Our findings concluded that the following air compressors brands are the best of the best.
Senco has been producing air compressors for decades. This company is known to produce some of the highest quality air compressors and they provide a wide range of air compressors. We liked that Senco offered so many options and features.
Makita is one of the most highly regarded manufacturers of power tools on the market. Their air compressors are made of the highest quality materials and use the most cutting edge technology, which results in some of the most powerful, durable and reliable air compressors that we tested.
California Air Tools
California Air Tools is also famed for producing high quality air compressors. We really like that they offer so many options and such a wide price range.
Rolair is another high quality producer of air compressors. You will find various types of air compressors with a wide range of features when you choose Rolair.