Guide to Air Compressors
The Complete Guide to Air Compressors
High-Performance Air Compressors for Every Application
Understanding what type of air compressor you need can be tricky. Our guide will help you decide which model works best for you. Whether you're powering air tools, inflating tyres or running industrial machinery, our extensive range of air compressors has you covered. Ranging from compact portable models to heavy-duty industrial models, we offer reliable solutions for workshops, garages, construction sites and more.
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What Is An Air Compressor?
An air compressor is a powerful machine that draws air from the atmosphere and compresses it to a higher pressure, storing it in a tank to be used for various tasks. The compressed air can then be released in a controlled way to power a wide range of pneumatic tools, machinery and equipment.
Whether you're working in a home workshop, automotive garage or an industrial setting, an air compressor is an essential piece of machinery that delivers consistent power and performance.
What Is An Air Compressor Used For?
Air compressors are a vital piece of equipment used across many industries. They power a wide range of air-powered tools, equipment, and machinery by delivering a reliable source of compressed air. Below are the most common uses of air compressors, organised by industry:
Automotive & Mechanical
- Inflating tyres quickly and accurately
- Spray painting vehicles in bodyshops
- Powering lifts and hoists in car repair bays
- Blow-off guns to clean engines and parts
- Commonly use low noise air compressors or oil-lubricated workshop compressors
Building & Construction
- Powering tools such as nail guns, jackhammers, impact wrenches, and drills
- Cleaning workspaces and equipment using compressed air jets
- Commonly use portable air compressors or petrol powered compressors
Industrial & Manufacturing
- Running production line machinery
- Controlling valves, pistons, and conveyors
- Packaging and labelling machinery
- Sandblasting and surface finishing
- Commonly use rotary screw compressors or high-capacity industrial compressors
What Type Of Air Compressor Do I Need?
The key factor in selecting an air compressor is understanding which tools and tasks you’ll be using it for. This will help determine the required CFM (cubic feet per minute) needed to operate your equipment effectively (more on this in the next section).
You should also think about how often and for how long you’ll use the compressor, as this will influence the size of the air storage tank you need. A small tank is sufficient for light, occasional home or hobbyist projects, while a larger tank is more suitable for regular or professional use.
Tank Capacity
Air compressors are available with various tank sizes, typically ranging from 4L to 500L. Generally, the larger the tank, the longer you can run the air compressor at a consistent power. However, the tank size you need will also depend on the tool you plan to use it with. All tools require a minimum airflow, measured in cubic feet per minute (CFM). To determine what tank capacity you need for a tool, multiply the tool’s standard cubic feet per minute (SCFM) by 6. SEALEY offer a large range of air compressors with tank sizes ranging from 4L to 500L.
Corded Or Cordless?
Corded air compressors require an electrical power supply to run the motor, so are best suited for use in factories and workshops where portability isn't needed and they can easily be connected to a power socket. Cordless air compressors however are powered by petrol or diesel, which means they can be used anywhere and are much easier to move around.
Oiled Or Oil Free?
When choosing a compressor, consider how frequently it will be used and whether contamination-free air is necessary. Oil-lubricated air compressors use compressor oil to lubricate moving parts, making them ideal for heavy-duty, continuous use in factories and industrial settings. Oil free compressors feature self-lubricating components and are better suited for occasional use, or where air purity is critical, such as in spray painting or clinical environments.
What Size Air Compressor Do I Need?
Compressors need to cool down between regeneration periods. Regeneration is when the pump replaces the air that has been used from the compressor’s air tank. The size of the tank will determine how long you can use your air tools before needing to let the tank fill up again.
A long job, such as sanding, will require a larger compressor. As an example, sanding with our Dust-Free Air Palm Orbital Sander Ø150mm [SA801] will require a compressor with a minimum Free Air Delivery of 6cfm. An air tool that requires a higher air output will drain the tank quicker than one that needs a lower air output, so the size you need depends on the job at-hand and how long the task will take.
What Is CFM And How Do I Calculate It?
Each air tool has a cfm rating, which defines the amount of air required to power the tool in cubic feet per minute (CFM). To know what capacity compressor you need, you first need to determine the highest cfm rating of the air tools you intend to use. If you intend using more than one tool at the same time, you will need to add the ratings of both tools to calculate the total cfm rating. A 50% safety margin then needs to be added e.g. a 4cfm tool would require a 6cfm output compressor.
Now you can look for the compressor that produces a high enough cfm output for your needs. When comparing models, ensure that you are reviewing the Free Air Delivery and not Air Displacement.
Oil Lubricated VS Oil Free Compressors?
Oiled air compressors use oil to lubricate their moving parts, while oil free compressors rely on components coated with a self-lubricating material. The best choice depends on how often the compressor will be used and whether clean, contaminant-free air is essential.
For example, if the compressor runs for extended periods each day, such as in a factory setting, an oiled model is more suitable due to its durability. Whereas, an oil free compressor is ideal for occasional use. It’s also the better option for applications like spray painting or clinical environments, where clean, oil free air is crucial.
Choose oil free if you need clean air, low maintenance, for occasional use or specific applications.
Choose oil-lubricated if you need durability for extensive, regular use or in demanding environments.
What Air Compressor Accessories Do I Need?
To operate an air compressor effectively and safely, it’s important to use the right accessories for your setup and tasks. Here’s a breakdown of the most common compressor accessories, what they do, and when to use them:
Air Hoses
Available in different lengths and materials (rubber, PVC, hybrid), air hoses need to be tough enough for the pressure rating of your compressor and flexible for ease of movement, especially in busy workspaces or mobile set-ups.
Fittings & Couplings
Fittings and couplings allow you to quickly attach and detach tools, hoses, and accessories without air leaks. They come in different styles (e.g. PCL, Euro, hi-flow) and sizes, so it’s important to match them with your compressor and tools.
Pressure Regulators
Different tools require different operating pressures, and a pressure regulator ensures you deliver the right amount of air for each job. By adjusting the regulator, you can prevent over-pressurising delicate tools while maintaining enough pressure for heavy-duty equipment.
Air Filters & Moisture Traps
Compressed air often contains moisture and particles, which can affect the performance and lifespan of your tools. These accessories filter out contaminants and are especially important for tasks like spray painting or operating air tools in sensitive environments.
Inline Lubricators
For oil-lubricated pneumatic tools, a lubricator injects a fine mist of oil into the airflow, reducing wear and tear. Ideal for workshops where tools see frequent, heavy use.
Air Supply Systems
An air supply system refers to the full set-up that delivers compressed air from your compressor to your tools or machines efficiently and safely. This often includes pipework, manifolds, hose reels, and distribution points.
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