Reviewed November 2026. Formulas are shown above the guide. Report an error or request a calculator.
Why leaks are expensive
Compressed air is one of the most expensive utilities in a factory: a compressor turns only a small share of its electricity into useful air power. Leaks waste that air around the clock, often 20–30% of a compressor's output in plants without a leak programme, and they are silent enough to ignore until someone puts a number on them.
Worked example
A plant with 20 leaks the size of a 1/16-inch hole, about 4 CFM each at 100 psi, loses 80 CFM. At a typical 20 kW per 100 CFM that is 16 kW of compressor power.
| Item | Value |
|---|---|
| Energy (16 kW × 6,000 h) | 96,000 kWh |
| Cost at $0.12 per kWh | $11,520 / year |
| Cost per leak | $576 / year |
| Repair round (20 × $50) | $1,000 |
| Payback | 32 days |
Getting the inputs right
- Flow per leak: an ultrasonic leak detector gives the best estimate. The presets are typical flows at about 100 psi; at lower pressure, leaks lose less.
- Specific power: modern rotary screw compressors use roughly 16–22 kW per 100 CFM at full load. Part-load operation makes each leaked CFM more expensive, not less.
- Hours: use the hours the system is pressurised, not the hours production runs. Many systems stay pressurised over weekends.
Frequently asked questions
How much does a 1/4-inch air leak cost?
At 100 psi a 1/4-inch leak passes roughly 60 CFM. At 20 kW per 100 CFM, 6,000 hours and $0.12 per kWh that is about $8,600 a year.
How do I convert l/s to CFM?
Multiply litres per second by 2.119. 10 l/s is about 21 CFM.
What percentage of compressed air is lost to leaks?
Surveys commonly find 20–30% in plants without a regular leak programme, and under 10% in well-managed systems.
Should I lower the system pressure too?
Yes. Leak flow falls with pressure, so reducing pressure by even 1 bar cuts leak losses and compressor energy.