Is a dive compressor worth it?
What a fill really costs you, how many fills a year make your compressor pay off, and how long it takes to pay back.
The compressor
Start from a typical model, then replace with the figures from your quote.
Actual output, service life and resale
Rated output is measured up to 200 bar: above that, the compressor slows down. Service life in hours matters when it runs a lot: it is then worn out before the planned years are up.
Your activity
How many cylinders you fill, and what you sell them for (or what you pay elsewhere today).
Fills per year
≈ 38 per week · 2,017 L of air and 9.0 min of running per cylinder.
Trips saved
If you currently drive back and forth to get fills elsewhere: the fuel and time the compressor saves you over a year.
Maintenance and running
The suggested values are orders of magnitude. The real ones are in the manual and on the cartridge sheet.
Electricity and room
Filters last less in a warm room.
Filters
A cartridge lasts ≈ 46 running hours, i.e. ≈ 307 cylinders like yours.
Servicing
Fixed costs each year
Fill operator labour
Leave 0 if fills are done by volunteers.
Profitable
You fill 2.7 times the break-even, and the outlay is recovered in 3.0 years.
Break-even point
Below break-even (red), costs are not covered. Above it (blue), each extra fill brings in €3.48.
Year after year
Cumulative cash: the initial outlay, then what the compressor brings in each year, plus resale in the last year.
Where the money for a fill goes
- Depreciationpurchase and installation, over 10.0 years44 %€0.80
- Fixed costsair tests, inspections, insurance14 %€0.25
- Electricity0.91 kWh per fill13 %€0.23
- Filters6.5 cartridges per year16 %€0.29
- Servicing1.0 per year14 %€0.25
- Cost per fill€1.82
What if you filled more or less?
Tap a row to apply it.
| Fills / yr | Cost per fill | Profit / yr | Paid back |
|---|---|---|---|
| 500 | €5.72 | −€861 | 24.3 years |
| 748 (break-even) | €4.00 | +€2 | 11.2 years |
| 1,000 | €3.12 | +€879 | 7.3 years |
| 2,000 | €1.82 | +€4,358 | 3.0 years |
| 3,000 | €1.39 | +€7,837 | 1.9 years |
| 4,000 | €1.20 | +€11,218 | 1.4 years |
| 6,000 | €1.02 | +€17,877 | 12 months |
Your compressor over a year
How it is calculated
1. Air per fill
In litres of free air. Z corrects for the real compressibility of air: at 230 bar, a cylinder holds about 5 % less air than Boyle’s law says.
air = cylinder volume × (final P ÷ Z − remaining P ÷ Z)
2. Running time
time = air per fill ÷ actual output
Actual output is a percentage of the rated output.
3. Electricity
hours × motor power ÷ 0.9 × price per kWh
The 0.9 is the efficiency of an electric motor: it draws a little more than its rated power.
4. Filters
A cartridge treats a given volume of air at 20 °C. That volume drops when it is hot (about half for every extra 10 °C), and at least the minimum number is replaced each year, even unused.
5. Servicing
Based on running hours, or at least once per period even if the compressor runs little.
6. Depreciation
(purchase + installation − resale) ÷ service life
Service life is the shorter of the planned years and the hours the compressor can run.
7. Cost, break-even and payback
- Cost per fill: all the year’s costs ÷ fills per year.
- Break-even: the number of fills from which income (and trips saved) covers all costs, depreciation included.
- Paid back in: (purchase + installation) ÷ cash generated each year, before depreciation.
No loan interest, inflation or VAT: this is an estimate to compare and decide, not an accounting statement.
Understanding compressor costs
The real cost of a fill
The real cost of a filled cylinder adds up electricity, filter cartridges, servicing, air quality tests, storage bank inspections, insurance and depreciation of the purchase. Example with a club compressor (250 L/min, 5.5 kW) and 2,000 12 L cylinders a year: about €1.82 per fill all-in.
Break-even and payback
Break-even is the number of fills per year from which income covers all costs, depreciation included. The payback time compares the investment with the cash generated each year. If you currently travel to get fills elsewhere, the savings count with the income.
The real volume of air in a cylinder
Above 200 bar, air no longer follows Boyle’s law exactly: a 12 L cylinder filled to 230 bar holds about 5 % less air than the simple calculation. The tool uses the compressibility factor of air. For pressure conversions, see the converter; to blend nitrox, the gas blender.
Frequently asked questions
How much does a scuba cylinder fill cost?
With a €15,000 club compressor (plus €3,000 installation) and 2,000 12 L cylinders a year, about €1.82 per fill all-in, depreciation included. The cost drops as you fill more.
Does a compressor pay off for a club?
With the same assumptions and fills sold at €4, the compressor becomes profitable from about 750 fills a year and is paid back in 3 years.
How long does a filter cartridge last?
It treats a given volume of air at 20 °C (stated on its sheet). That volume is roughly halved for every extra 10 °C in the room: a cool, ventilated room makes filters last.
Is an air quality test mandatory?
For professional use, at least once a year. Its price ranges from about €40 (kit) to €150 (laboratory).