- Author
- Byron Raal, CAS Founder-Editor About the author
- Date last checked
- 29 August 2026
Running an air compressor costs far more than buying it. Across the machine’s working life, energy dominates the total cost of ownership; across the industry you’ll see 70 to 80 per cent quoted, with the purchase price and maintenance sharing the rest. That range is an industry estimate, not a precise figure. What the US Department of Energy’s Compressed Air Sourcebook actually says is that electricity is by far the largest cost of owning a compressor over its life, and that a compressor’s lifetime electricity bill typically exceeds its purchase price. The maths behind your own number is simple: annual cost = kW x operating hours x tariff, adjusted for load profile. At an indicative Australian tariff of $0.30 per kWh, a 15 kW compressor running two 12-hour shifts (about 6,000 hours a year) at full load costs about $27,000 a year in electricity alone. A 45 kW machine on the same duty costs about $81,000. This guide gives you the formula, a cost table by size band, and the four levers that actually cut the bill.
The formula, and a worked example
There’s no mystery to compressor running cost. It’s three numbers multiplied together, then adjusted for how hard the machine actually works:
Annual electricity cost = kW x hours per year x $ per kWh, adjusted for load profile.
Take a 15 kW rotary screw compressor on a two-shift site:
- kW: 15
- Hours: two 12-hour shifts, five days a week, is about 6,000 hours a year (24 hours x roughly 250 running days). If you run two 8-hour shifts, use about 4,000 hours instead
- Tariff: $0.30 per kWh, an indicative Australian commercial and industrial rate for 2025-26. Your contract rate might be $0.22 or $0.38. Use your actual number.
15 x 6,000 = 90,000 kWh. At $0.30 per kWh, that’s $27,000 a year. Depending on the model, that can be more than the machine cost to buy, spent on electricity every single year it runs those shifts.
Running cost formula
Three numbers, one electricity bill
Multiply kW by hours by tariff, then adjust for how hard the machine actually works.
Annual electricity cost = kW × hours per year × $ per kWh
adjusted for load profile
Worked example: 15 kW rotary screw on a two-shift site
nominal motor rating
two 12-hour shifts, about 250 running days
indicative 2025-26 C&I rate; use your own
$27,000 a year
Same machine, single shift (2,000 h/yr)
about $9,000 a year45 kW machine on the same two-shift duty
about $81,000 a yearAssumes full load for every running hour and nominal motor kW as an illustrative proxy for electrical input. Part-load operation pulls the real bill down; package input above the nominal rating, poor control, leaks and pressure creep push it up.
Source: CAS running cost formula at an indicative $0.30 per kWh, full load.
Two honesty notes before you take that number to your finance team. First, it assumes the compressor is loaded the whole time it runs; the load profile section below covers what happens when it isn’t. Second, the kW in a compressor’s name is the nominal motor rating, and that is not what your meter sees. The meter sees the whole package: motor, cooling fan, drive and control losses together. Total package electrical input runs higher than the nominal motor rating, and by how much varies from model to model, so check the CAGI performance data sheet for your machine’s total package input power rather than leaning on a rule of thumb (Atlas Copco’s GA37, for example, pairs a 37.3 kW nominal motor with a 43.3 kW package input at full load, about 16 per cent higher), and the only number that settles it is metering your own supply. The table below uses nominal motor kW as an illustrative proxy for electrical input, so your real bill can read higher or lower than these cells: part-load operation pulls it down, while package input above the nominal rating, poor control, leaks and pressure creep push it up.
Running cost by compressor size
Every cell below is computed from the formula: nominal motor kW x hours x $0.30 per kWh, at full load. The nominal motor kW stands in as an illustrative proxy for electrical input, so real bills can land higher or lower than these cells: part-load operation pulls them down, while package input, poor control, leaks and pressure creep push them up (see the package-input note above). No rounding tricks, no “typical customer” fudges. Recompute any cell yourself. To price the air rather than the machine, see what one cfm of compressed air costs, which works from total package input rather than the nominal motor rating used here.
| Compressor size | Single shift (2,000 h/yr) | Two 12-hour shifts (6,000 h/yr) | Continuous (8,760 h/yr) |
|---|---|---|---|
| 7.5 kW | $4,500 | $13,500 | $19,710 |
| 15 kW | $9,000 | $27,000 | $39,420 |
| 22 kW | $13,200 | $39,600 | $57,816 |
| 37 kW | $22,200 | $66,600 | $97,236 |
| 45 kW | $27,000 | $81,000 | $118,260 |
| 75 kW | $45,000 | $135,000 | $197,100 |
Assumptions for every cell: $0.30 per kWh as an illustrative energy-rate assumption, not a national industrial tariff benchmark (actual rates vary by state, retailer and contract, so substitute your site’s marginal energy rate), full load for every running hour, nominal motor kW used as an illustrative proxy for electrical input. Annual cost = kW x hours x $0.30. Many industrial bills also carry demand or capacity charges that compressor operation affects, and this page’s dollars-per-kWh model doesn’t count those.
Read the 75 kW continuous row again: nearly $200,000 a year. It’s common to see sites paying figures like that to run a compressor nobody has right-sized or leak-tested in years. If the size itself is the question, start with the air compressor sizing guide before you spend a cent on efficiency measures; the cheapest kilowatt is the one you never install.
What changes the number
The table is the honest baseline. Four things move your real bill off it, in both directions.
Load profile. A compressor that runs 6,000 hours doesn’t necessarily make air for 6,000 hours. Fixed-speed machines idle unloaded between demand peaks, and an unloaded compressor still draws a meaningful fraction of its full-load power while delivering nothing. That’s the part-load penalty the US DOE Sourcebook flags on fixed-speed machines: your cost per useful cubic metre of air climbs as your average load drops. If your compressor is loaded 60 per cent of the time, your bill won’t be 60 per cent of the table figure. It’ll be worse than that, and the gap is pure waste.
VSD or fixed speed. A variable speed drive matches motor speed to demand instead of cycling between loaded and unloaded. On sites with genuinely variable demand, that closes most of the part-load gap. On a site running flat out at constant demand, a VSD buys you little; the machine would be fully loaded anyway. This is why “VSD saves 35 per cent” sales claims deserve a raised eyebrow: the saving depends entirely on your demand profile, which is exactly what a logged energy audit measures before anyone quotes you.
Leaks. The US DOE puts typical leakage at roughly 20 per cent of production capacity for a poorly maintained plant, with losses as high as 20 to 30 per cent in the worst systems (see the CAS leak-cost report for the Australian dollar figures). On the 45 kW two-shift machine above, 30 per cent of $81,000 is $24,300 a year spent compressing air that hisses straight back out of the pipework, and that is the upper-bound illustration, not a promised saving. Leakage is a flow percentage; it only becomes a bill percentage when your control system converts the reduced demand into reduced power by unloading, slowing or switching off compressors after the repairs. A single 3 mm leak at 7 bar costs roughly $3,500 to $6,900 a year on its own (at 4,000 to 8,000 operating hours a year and $0.30 per kWh, per our leak-cost model), and plenty of never-surveyed plants have dozens.
Pressure. Every bar of unnecessary system pressure adds roughly 7 per cent to energy use, and higher pressure makes every leak leak faster. Plenty of sites run at 7.5 bar because one tool somewhere allegedly needs it, when the whole plant would run happily at 6.5. That habit costs real money every hour of every shift.
The four levers, ranked by payback
If the table above just put an uncomfortable number on your plant, here’s the order to attack it in. Fastest payback first.
1. Fix the leaks. Cheapest kilowatt-hours you’ll ever recover. An ultrasonic leak survey finds and tags leaks in a day, fixes are mostly fittings, joints and hose ends, and the saving starts the moment each leak is sealed. With roughly 20 per cent of system energy on the table, and more in the worst systems, a leak program on a mid-size site routinely pays for itself in months. Put your own numbers into the leak cost calculator and see what a single 3 mm hole is costing you.
2. Drop the pressure. Nearly free. Find the true minimum pressure your processes need, then lower the setpoint band toward it. At roughly 7 per cent energy per bar, taking a plant from 7.5 down to 6.5 bar can save roughly 7 per cent of compressor energy for the cost of a commissioning visit, and it shrinks every leak on site at the same time.
3. Sort the controls, then consider a VSD. Sequencing, storage and setpoints on the machines you already own come first; they cost little and stop compressors fighting each other. If a logged demand profile then shows big swings, a VSD on the trim machine can close the part-load gap. Capital cost is real, so paybacks run longer than leaks or pressure; one to three years is common in retrofit projects, and yours depends on installed cost, demand profile and running hours. Buy the data before the drive.
4. Recover the heat. The large majority of a compressor’s electrical input leaves as heat, and much of it is recoverable for space heating or hot water. It’s the biggest untapped stream in the room but the payback depends on you actually needing the heat somewhere nearby. If you’ve got a use for it, run the numbers in the heat recovery ROI calculator.
Work the list in order. Leaks and pressure fund the audit; the audit builds the case for controls and heat recovery. A structured compressed air energy audit scopes all four levers against logged data from your own site, which beats every rule of thumb on this page.
Frequently asked questions
How much does it cost to run a 15 kW air compressor in Australia?
About $27,000 a year in electricity on two 12-hour shifts, roughly 6,000 hours a year: 15 kW x 6,000 hours x an indicative $0.30 per kWh, assuming full load. On a single shift of about 2,000 hours, the same machine costs about $9,000 a year. Your real figure depends on your contract tariff and how heavily the machine is actually loaded, so substitute your own rate and hours into the formula.
How do I calculate my compressor’s running cost?
Multiply the compressor’s kW by its annual running hours, then by your electricity tariff in dollars per kWh. A 22 kW machine at 6,000 hours and $0.30 per kWh is 22 x 6,000 x 0.30, which is $39,600 a year. Then adjust for load profile: a fixed-speed machine that spends much of its time unloaded still draws significant power, so metered reality usually sits above the naive full-load-fraction estimate. For a defensible figure, log the machine’s electrical input over a representative week or two.
Is electricity really most of what a compressor costs?
Yes. Across the industry you’ll see energy quoted at 70 to 80 per cent of total cost of ownership, with purchase price and maintenance making up the rest; that’s an industry estimate, not a precise figure. What the US Department of Energy’s Compressed Air Sourcebook does say is that electricity is by far the largest cost of owning a compressor over its life, and that it typically exceeds the purchase price. Either way, the direction is beyond argument: a compressor is an electricity bill with a machine attached.
Does a variable speed drive compressor cost less to run?
Only when your demand actually varies. A VSD matches motor speed to demand, so it removes most of the energy a fixed-speed machine wastes idling unloaded between peaks. On a site with steady, near-full load, a VSD delivers little because the compressor would be fully loaded either way. The honest answer comes from a logged demand profile, not from a brochure.
How much do air leaks add to the bill?
Plenty. The US Department of Energy puts typical leakage at roughly 20 per cent of production capacity for a poorly maintained plant, with losses as high as 20 to 30 per cent in the worst systems. On a 45 kW compressor costing about $81,000 a year on two 12-hour shifts (about 6,000 hours a year), a 30 per cent leak rate is roughly $24,300 a year as an upper bound; the realised saving depends on your controls unloading, slowing or switching off compressors once the leaks are fixed. A single 3 mm leak at 7 bar costs about $3,500 to $6,900 a year by itself, at 4,000 to 8,000 operating hours a year and $0.30 per kWh.
What electricity tariff should I use in the calculation?
Use the actual marginal rate from your electricity contract, not an average. The figures on this page use $0.30 per kWh as an illustrative energy-rate assumption, not a national industrial tariff benchmark; real contracted rates vary widely by state, retailer and load size, and large industrial sites on negotiated contracts can pay well under that. Many industrial bills also carry demand or capacity charges that compressor operation affects, which this page’s dollars-per-kWh model doesn’t count. The formula doesn’t care which number you use, so use the true one.
Put a real number on your own plant
Actual running cost depends on your electrical input, tariff, operating hours and control behaviour. Describe the measurements you have and what you want an audit or leak survey to establish. CAS does not sell equipment or perform the audit. We can review your brief and discuss a suitable Australian provider if one is available. We ask for your written permission before an introduction and explain any referral payment arrangement. There is no cost to enquire.
Tell us your installed compressor kW, your operating hours and your postcode. We can review your brief and discuss a suitable Australian provider if one is available. We ask for your written permission before an introduction and explain any referral payment arrangement. There is no cost to enquire.
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