Compressed air leak cost calculator
Enter the diameter and number of leak holes on your line. With an orifice flow model, see the leak flow, yearly energy use, cost and the payback time of repairs.
The calculation runs in your browser; the values you enter are not sent anywhere.
- Annual leak cost
- €7,275
- Total leak flow
- 20.73 L/s · 1.244 m³/min
- Power the leak costs at the compressor
- 8.084 kW
- Annual energy
- 48,501 kWh/year
- Air wasted per year
- 447,702 m³/year
- Total number of holes
- 12
- Total repair cost
- €600
- Payback time
- 0.99 months
Flow is sonic (choked): flow is proportional to absolute pressure.
Hole groups
| Diameter | Count | Annual cost | Share |
|---|---|---|---|
| 3 mm | 2 | €4,677 | 64% |
| 1 mm | 10 | €2,598 | 36% |
Assumptions
- Ideal gas, isentropic orifice flow, k = 1.4, air temperature 20 °C; the leak discharges to atmosphere (1.01325 bar).
- Above a pressure ratio of about 1.893 (gauge pressure about 0.9 bar) the flow reaches sonic speed (choked) and flow depends only on absolute pressure and hole area; below that the subsonic formula is used.
- Free air delivery is stated at 20 °C and 1.01325 bar (density about 1.204 kg/m³).
- Energy = flow × specific power × hours. The compressor is assumed to be at full load all the time; unloaded running and part-load change the specific power.
- A common leak profile is many small joints and cracks; the estimated hole diameter is the biggest uncertainty (flow grows with the square of the diameter).
ṁ = Cd · A · P₁ · √(k/(R·T)) · (2/(k+1))^((k+1)/(2(k−1))) (choked flow) · flow = ṁ / ρ_ref · energy = flow · kW/(m³/min) · hours · cost = energy · price
The result is an order-of-magnitude estimate from a model with a round, sharp-edged hole. The real leakage should be verified by ultrasonic measurement, the pressure decay during non-production time, or a flow measurement. This tool gives a first assessment.
Let's look at how much of the leakage can be monitored from your compressor and line data, and what that means for the maintenance plan.
Request a conversation01
How to use it
A
Enter the line pressure, yearly operating time, electricity price and compressor specific power.
B
Enter the diameter and number of leak holes as rows.
C
Read the annual cost and flow; enter the repair cost to see the payback time.
02
Why compressed air is expensive
Most of the electricity used to make compressed air ends up as heat; air at the point of use is an electrically expensive energy carrier. That is why leaks are a silent but continuous cost item: a leak carries on even when production is stopped (if the line stays pressurised).
Leak flow grows with hole area, that is with the square of the diameter: a hole of twice the diameter leaks four times as much air. A few large leaks therefore often cost more than hundreds of small seeps.
03
The model behind the calculation
The leak is modelled as an orifice open to atmosphere. When the line pressure is above about 0.9 bar gauge the flow through the hole reaches sonic speed (chokes) and flow is set only by absolute pressure, hole area, temperature and the discharge coefficient Cd. At lower pressure the subsonic flow formula is used.
Free air delivery (FAD) is the mass flow divided by the air density at 20 °C and 1.01325 bar. Electrical power is this flow times the compressor's specific power (kW/(m³/min)). Specific power depends on the compressor type, load and pressure setting; you need to enter your own value.
04
How to find leaks and when repair pays
The practical way to find leaks is an ultrasonic detector; soapy water also works on small joints. The easiest measurement is to look at the share of time the compressor is loaded while production is stopped: if the compressor is still loading with no production, the line is leaking.
Repair cost is often far below the annual cost of the leak, so payback is usually short. Compare the tool's result with the unit repair cost to set priorities. Also consider that repaired leaks reappear over time: a regular leak survey programme is worthwhile.
FAQ
- How much does a compressed air leak cost?
- It depends on hole diameter, pressure, operating time and electricity price. From these values the tool calculates the flow with an orifice flow model, and with the compressor's specific power the yearly energy and cost; even a few holes are significant per year at the example values.
- What is the Cd coefficient and which value should I enter?
- It is the loss coefficient, the ratio of real to ideal flow through the hole. Roughly 0.6–0.65 is used for a sharp-edged round hole. Real leaks (cracks, threads, gaskets) behave differently, so read the result as an order-of-magnitude estimate.
- Where do I find the specific power?
- It is given in the compressor's data sheet or performance test as power per free air delivery (kW/(m³/min)). Use your own machine's full-load value.
- Does the leak continue outside operating hours?
- Yes, as long as the line stays pressurised. Include the hours when the line stays pressurised even with production stopped in the operating time field.
- How many holes can I enter at once?
- Each row is the count of holes of one diameter; you can add up to eight rows. Group real leaks into equivalent diameters.
- How is the payback calculated?
- Total repair cost (cost per hole × total number of holes) is divided by the annual leak cost and converted to months. It assumes the repair removes the whole leak and leaks do not reappear.
Monitor leaks and energy loss with data
Let's look at how well leakage and inefficiency can be monitored from your compressor and line data, and what that means for the maintenance plan.