What Should You Consider When Selecting an Air Compressor?

Start With Air Demand, Not Horsepower

One of the most common compressor purchasing mistakes is comparing machines by motor power alone.

A professional specification starts with two figures:

required pressure and required airflow.

Airflow is normally expressed as CFM, L/s or FAD, depending on the supplier and market.

Atlas Copco's UK sizing guidance specifically warns that machines with identical motor ratings can deliver different airflow at different pressures.

Calculate the Airflow Required by Your Equipment

List every air-consuming tool or machine.

Then identify which of them may operate simultaneously.

The compressor should provide enough usable airflow to cover that demand without repeatedly stopping work while the receiver rebuilds pressure.

An undersized system creates pressure drops.

A substantially oversized system can also increase purchase cost and energy consumption.

Understand FAD Before Comparing Compressors

Free Air Delivery (FAD) is particularly important when comparing professional compressors.

Do not assume that an intake displacement figure is identical to actual usable delivery.

When comparing different suppliers, check whether the published airflow figure represents:

• Intake displacement

• FAD

• CFM

• Flow at a specific working pressure

A meaningful comparison requires equivalent measurement conditions.

Match Pressure to the Highest Required Consumer

Higher pressure is not automatically better.

The system should provide enough pressure for the most demanding piece of equipment, while allowing for pressure losses in:

• Pipework

• Filters

• Dryers

• Regulators

• Couplings

Overspecifying pressure increases energy demand. Atlas Copco notes that higher operating pressure requires additional power even where required flow remains unchanged.

Consider Duty Cycle Before Choosing Piston or Screw

A reciprocating compressor can be a strong choice for intermittent workshop use.

A rotary screw compressor is generally better suited to longer sustained demand.

This distinction is more useful than simply saying piston compressors are for small companies and screw compressors are for large factories.

UK manufacturer guidance specifically highlights duty cycle as a major purchasing criterion.

Receiver Size Is Not Compressor Output

A large receiver provides stored air.

It can absorb short peaks in demand and reduce rapid cycling.

It does not increase the compressor element's continuous airflow.

Select receiver capacity only after determining how much air the site consumes and how frequently demand peaks occur.

Check Air Quality Requirements

Compressed air used for general workshop tools has different quality requirements from air used in food, pharmaceutical, painting or contamination-sensitive processes.

Depending on the application, the system may require:

• Filtration

• Refrigerated or adsorption drying

• Oil-free compression

• Condensate management

Air quality therefore needs to be included in the initial compressor specification rather than treated as an accessory later.

Include Noise and Installation Conditions

A workshop located close to offices, residential premises or customer areas may place greater value on low noise.

Also consider:

• Ventilation

• Ambient temperature

• Space around the compressor

• Service access

• Electrical supply

• Pipework layout

The machine has to fit the site as well as the airflow calculation.

Compare Total Operating Cost

Purchase price is only one part of compressor ownership.

Electricity, servicing, replacement parts and production downtime all contribute to lifecycle cost.

For high operating hours, energy efficiency can become more important than the initial price difference between models.

Specify a Compressor Around Your Actual Load

Compare the JBS air compressor range, review suitable commercial applications, and read the Types of Air Compressors guide before selecting a system. You can also review applications such as Auto Detailing Centres, where compressed air forms part of a wider equipment setup. Send your required pressure, FAD/CFM and daily operating hours to request a technical quotation.