Determining air compressor size

When purchasing a new compressed air system, one of the biggest challenges can be sizing your product.

Air compressor size can affect capacity, pressure demands, costs and system efficiency, so it’s important to get it right.

To do this, you need to understand the application and usage of your compressed air system and consider three main factors: capacity, pressure and load factor.

View of a hand solving a math equation with calculator beside


The capacity of your compressed air system can be determined by summing the requirements of the tools and process operations needed for the site.

The total capacity required will be the average air consumption for each, with the load factor determining how and when the air is used. For example, high short-term air demands may be met by stored air in an air receiver.

The pressure gauge on the air compressor


Different tools and processes require different pressures, so understanding the flow and pressure requirements of your facility is integral when choosing a compressed air system. Pressure refers to the amount of force a system needs to be able to perform a set amount of work at any given time, and an air compressor needs enough pressure to perform efficiently.

Pneumatic tools and equipment should have a pressure rating as listed by their respective manufacturer, and your objective should be to meet the respective pressures required after taking into account pressure losses through pipe lines and treatment equipment, whilst not over-pressurising the system. Over pressure not only causes inefficient energy consumption, but can increase consumption through unregulated air usage and system leaks.

Load factor

Another important aspect to determining the correct air compressor size and type is how your compressed air system requirements will change over time.

Facilities with large variations in air demand will require a system that operates efficiently under part load, which depends on the unloading method. Inlet valve modulation controlled air compressors can use 70 percent of their full load power while idling, and not generating any useful compressed air! On the other hand, variable speed air compressors unload almost linearly, using almost the same ratio of power-to-output along the loading curve.

Variable speed drive compressors and/or multiple compressors with sequencing controls may provide the most economical solution in this case.

Compressor for supplying air to the dental drill

Extensive product range

Our extensive range of Australian made compressed air products offers a solution for all your needs, including compressed air piping.

From air compressors through to compressed air storage, treatment and distribution, we’ve got you covered. And if none of our standard compressed air products are suitable, we offer custom-built solutions to meet your individual requirements.

Our product range and large stock levels, combined with our comprehensive spare parts inventory, ensure we maintain your compressed air system’s reliability and efficiency while reducing whole-of-life operating costs.

Learn more about our compressed air products.