The U.S. Department of Energy publishes leakage rates in cubic feet per minute for several approximately equivalent orifice diameters and supply pressures. This calculator uses that table, interpolates between the published pressure rows, applies the selected opening-shape factor, then converts the lost airflow into compressor power and annual electricity cost.
The default specific power is 18 kW per 100 cfm, a published typical example used by both DOE and Kaeser. Actual compressor performance can be materially different, so use the model's CAGI or manufacturer performance data when available.
Take an approximately 1/8-inch sharp-edged leak at 100 psig. The DOE table gives 25.22 cfm before the published sharp-edge correction. Applying ×0.61 gives about 15.38 cfm. At 18 kW/100 cfm, 8,000 operating hours and $0.15/kWh, the estimated electricity cost is about $3,323 per year.
- SIZEEquivalent orifice diameter is an approximation. A cracked fitting, valve leak or quick-connect does not necessarily behave like a clean drilled hole.
- SHAPEDOE's published correction factors materially change the result: ×0.61 for sharp-edged openings and ×0.97 for well-rounded openings.
- POWERThe default 18 kW/100 cfm is a typical example, not a rating for your compressor. Use model-specific performance data when possible.
- HOURSCount the hours the system remains pressurised at roughly the entered pressure. A plant that shuts air off nights and weekends should not use 8,760 hours.
- AUDITDOE identifies ultrasonic acoustic detection as the preferred way to locate leaks. This calculator estimates the cost of a known or suspected leak; it is not a whole-system audit.
A larger opening loses more air, but pressure changes the leak rate too. In the DOE table, an approximately 1/8-inch opening rises from 18.62 cfm at 70 psig to 30.65 cfm at 125 psig before the opening-shape correction.
That is why a cost estimate based only on a guessed hole size can be misleading. Use the pressure at or near the leak, not simply the compressor's maximum nameplate pressure.