Don’t Let Your Energy Dollars Disappear into Thin Air

This article appeared in the April 2025 issue of MiMfg Magazine. Read the full issue and find past issues online.

For the average manufacturer, 20-30 percent of total energy consumption is related to compressed air. According to the U.S. Department of Energy, it is estimated that up to 20-30 percent of the compressed air generated by industrial air compressors is lost due to leaks and inefficient usage.

If you can hear a leak, it is probably at least one CFM in size or larger. A one CFM air leak costs about $50 per shift annually (assuming a cost of about $0.13/kWh). Multiple shifts increase that number by two or three times and if your system runs 24/7/365, the cost increases to over $200. Even small leaks can easily add up to thousands in annual costs.

Detect and Repair Leaks

Compressed air professionals find leaks using an ultrasonic leak detector using the high-frequency sound emitted by leaks to pinpoint their location. Ultrasonic detectors “listen” for pinprick leaks emitting sound in a range of about 40 kHz, about twice the frequency detectable by humans.

As the operator moves around the facility wearing headphones, the detector will indicate whether they are getting closer to or farther from the leaks it “hears.” The detector leads the operator right to the source of the leak and estimates its size in CFM based on the decibels recorded. This process is generally done while the plant is operating and does not interfere with production. Upon finding a leak, the operator then “tags” and photographs it to mark it and later return to repair the leak.

Most leaks can be found in the pipes, hoses and connectors that hook a piece of equipment into the compressed air system. Some leaks may be difficult or not feasible to repair such as when they occur in an integral portion of a production machine. Typically, somewhere in the 20-25 percent range of leaks are not practical to repair.

Another major cause of wasted energy is system over-pressurization. Many times, manufacturers are operating compressors in the 125 PSI range while its operating functions are receiving air at 75 PSI. Ideally, a system without leaks should operate at a pressure of about 10 PSI above the pressure received at its workstations.

By forcing the compressor to cycle more frequently, leaks shorten the life of the system’s components, increase maintenance requirements, increase downtime and can lead to adding unnecessary compressor capacity.

Save 75-100% On Repairing Leaks

Michigan’s electric utilities, in their efforts to reduce generation needs, are offering significant “Energy Waste Reduction” rebates of the cost to find and repair compressed air leaks. In almost all cases the payback period will be short and in many cases the rebates are large enough that leaks can literally be fixed without any out-of-pocket cost. To qualify, however, the compressor capacity at the site must be at least 50 horsepower.

Leaks don’t stop happening. Before long, leaks will come back somewhere. Because of this, utilities allow manufacturers to receive rebates once each year. EnStar strongly urges every manufacturer to establish a program to control their compressed air leaks, including taking advantage of the utility rebates available. The savings are real. As MMA’s energy partner, EnStar has helped MMA members save as much as $44,000 annually. Don’t let your air go to waste.

About the Author

Don Johns is EnStar Energy’s Founder and President. He is a legend in the energy field and worked at the Michigan Public Service Commission for 22 years before founding EnStar with a group of partners. He may be contacted at mmaenergysavings@enstarenergy.com.

EnStar Energy LLC is an MMA Industry Member and has been an MMA member company since May 2014. Visit online: enstarenergy.com.