How Valuable is a Free Air System Audit?

Free Compressed Air Audit vs. Permanent Monitoring: What is your best option?

Optimal compressed air system performance, defined by efficiency, reliability and air quality, has now become the main goal when operating, installing, purchasing or designing compressed air products. Whether you are the air compressor manufacturer, distributor or end user – everyone in the compressed air industry needs to be aware and work towards these goals.

Baselines Developed by Permanent Monitoring vs. Temporary Compressed Air Audits

Rapidly rising energy costs, tough economic times and the need to reduce costs are factors impacting all businesses operations. This is driving a wave of demand for energy reduction measures and technologies. Compressed air systems, a very expensive utility, have become the first target for energy reduction measures in most industrial facilities today.

“Free” sales-based audits have become readily available, in the compressed air industry, from many organizations pushing product sales.  How reliable are the results and recommendations from these free audits lasting a maximum of ten days? What is the actual value to the bottom line for an end user?  These are the questions typically raised surrounding free audits. Since free doesn’t exist, what’s the catch? Do factories have another option? Yes, they do.

Airleader is heavily involved in compressed air audits, working with several utilities in the United States and in other countries around the world. For larger compressed air systems, we recommend the utility providers spend the extra incentive money to invest in a permanent monitoring system – rather than ten days of temporary metering for an audit. A permanent monitoring system can provide a very solid baseline, developed over several weeks or months. It also allows one to examine and quantify various metrics such as weekend leak rates, and different loads based on many more production day profiles. Creating a more robust baseline profile allows an audit to better identify several corrective measures such as storage, piping changes, control systems or leak repair – and precisely quantifying the ROI for each measure and prioritizing them with budgets or timelines.

An Audit Process Using Two Months of Data

We recently performed a compressed air audit at a large manufacturing facility running several large air compressors at two separate locations in the plant. Metering equipment was installed including kW meters, flow meters and pressure sensors throughout the facility. A thorough leak audit for the whole facility was also performed. The audit process took just under two months to collect the data, find the system inefficiencies and make the proper recommendations.

The compressed air audit report was presented to the client identifying substantial inefficiencies due to poor piping, improper control of the air compressors, excessive unloaded compressor times, huge amounts of air leaks, and to everyone’s surprise, the discovery that the system runs on two different pressures as the systems are separated via underground piping networks. As one can imagine, getting to the bottom of a system like this was going to be a massive undertaking. It would need to be done in stages, using a tremendous amount of instrumentation.

The first measure had to be a master controller. With the master controller, we would then be able to control the compressors and correlate the data collected to production demands and leak loads.  Stage one included the master controller, large air receivers, a large energy efficient compressed air dryer and a large VFD air compressor to trim the base loaded units. Once the system was installed the savings were immediate, unloaded air compressor power went from 70% to 15% while decreasing the motor cycles – saving the motor and bearing life of the air compressors.


Metering and Monitoring of Compressed Air Flow – Click here to enlarge.

Five Months After the Audit

With proper control of the compressed air system now in hand, we began the task of identifying further measures through the data collection system and permanent metering installed. This quickly identified a leak rate >50%, which on a system consuming more than 10,000 cfm at times, is a massive volume of leaks. We identified the leak rate by correlating flow rates during down-time on Sundays and Saturday off shifts. This data was compared to the data from the kW meters (on the air compressors) which allowed us to build a proper ROI for the client. Without the permanent metering, we would have had no way of accomplishing this task.  The plant, however, needed to understand the data to believe in the project.

I remember coming back to the site, five months after the audit, to do some customer training on the master controller. Just as I getting ready to leave, I was told I had to wait for their system analyst to come down. I asked the maintenance manager, “What analyst?” He responded saying the analyst was from the accounting department but he didn’t know what the analyst wanted. Soon the gentleman arrived, carrying some printed graphs from the monitoring system, similar to graph 1. He asked me, “Can I trust the data provided from your system?” I looked at the data and said, “Yes you can, why do you ask?”

The analyst was shocked that on Sundays, when the plant was closed, the flow rate was 3500 CFM and even more shocked when he realized that the plant leaks the same amount 365 days a year. The next question from the Analyst was, “How can you confirm this is the correct flow rate?” I then used the kW data, to show that yes, three air compressors were running loaded – again confirming the leak rates were correct.


Table 1: Air Compressor Performance during a full week – Click here to enlarge.

We printed the weekly performance table (table 1) and a weekend day performance table (table 2), allowing us to perform the following calculations.

Leakage = 16,789 kWh (Saturday to Friday) = 117,523 kWh / week

Total Air Demand (Saturday to Friday) = 206,666 kWh/ week

    • 56.9% of compressed air is lost through leaks
    • At 10 cents/kWh = leaks represent US $611,120 annually


Table 2: Air Compressor Performance during the weekend – Click here to enlarge.

Within a few weeks of our conversation, a plan was in place to install multiple flow meters and pressure sensors throughout the facility to find the losses in the vast piping network. Identifying the leak losses of 6.1 million kWh triggered the immediate installation of the sensors, which through the webserver software on the master controller, allowed the client to identify the areas of the plant that should be targeted for leak repair first. Using the tools now available to the Client, a long-term leak prevention strategy is in place by setting limits to the flow across the flow meters triggering an email or alarm if the flow (CFM) should start to climb beyond the existing “best practice” values.


Being involved in hundreds of audits of facilities, like the one described, we see the same thing repeatedly. Typically a free audit is performed and a large VFD air compressor is installed. The client carries on with production never realizing what’s going on with the system. Installing a VFD air compressor is a supply side addition, which may or may not generate savings, depending on how it is sized and applied.

A new VFD air compressor  doesn’t change the demand side of the compressed air system – where the air is being used and/or wasted.  The new VFD air compressor may help supply the compressed air leaks and inefficiencies at a better specific power – but it will not rectify the issues still present within the system. Opting for a more expensive, but much more detailed audit of the entire compressed air system is the only way to find these kinds of savings. Combining this type of audit with permanent metering and monitoring is a long-term sustainable solution and not just a way to purchase a new air compressor.

Permanent metering and monitoring will also provide a continuous 24/7 audit helping to sustain the savings – after compressed air system improvements are made. This provides the plant the tools to adhere to ISO 500001 energy guidelines, provide the data for utility incentives without the costs of a post-audit, as well as justify the ROI to carry out any future efficiency upgrades.


“You cannot manage what you do not measure.”

This article was published in Compressed Air Best Practices. To read the original article or similar Air Compressor System Assessment articles, visit:






North American Lighting Saves $91,000 Annually with Airleader Master Controller

North American Lighting has reduced its total compressed air energy use by 27 percent – and in the process – saves over 1,100,000 kWh/year for a total annual savings of $91,000. The project payback was less than a year. Also noteworthy is that the savings will increase as the costs of energy increase, a point often overlooked.

Many maintenance managers know a combination of sizes and types of air compressors is a good thing for efficiency of a compressed air system. This allows a facility to match demand to a correctly sized compressor. The challenge has traditionally been sequencing the compressors to run optimally. Most controllers on the market can only sequence the order in which air compressors run without selecting the best combination for current demand.

This is where the Airleader Master Controller outperforms other controllers. According to Jan Hoetzel, Airleader North America, “Our master controllers can control anywhere up to 32 compressors in multiple locations. We install a control module into each air compressor that is connected to the Master controller. Depending on the compressor locations, we can either wire them directly to the controller or utilize the existing Ethernet network to control the compressors remotely, as was the case with the North American Lighting Project.”

Following a week of data logging the North American Lighting system, a baseline was established and the system was analyzed. It was discovered the customer was running too many air compressors at the same time and their large VSDs were running fully loaded rather than trimming.  Airleader simulation software uses that data to demonstrate how a master controller could reduces the unloaded energy.

The Airleader Master II Controller could:

  • Match air demand and supply
  • Control multiple air compressor load/unload and a VSD unit from various compressor OEMs.
  • Use only one Master Controller to manage two locations via an Ethernet network, reducing installation and cabling costs.
  • Ensure the system ran efficiently now and into the future, as well as providing the ability to make adjustments to the air compressor system settings remotely and providing historical data for further analysis when required.

How healthy is your air system? Are there opportunities to reduce the amount your facility spends on compressed air and maximize the operation of your system?

You can download and read the full article in Compressed Air Best Practices, at the following link:

Airleader Compressed Air Best Practices 12.2018 


Compressed Air Challenge Fundamentals Training

Compressed Air Challenge© has announced they will be offering their Compressed Air Fundamentals Training in Grand Rapids, Michigan November 29, 2018.

The Compressed Air Challenge© is a voluntary collaboration of industrial users; manufacturers, distributors and their associations; facility operating personnel and their associations; consultants; state research and development agencies; energy efficiency organizations; and utilities, that are determined to help you realize the benefits of smart compressed air management.  As a result, they have developed the Fundamentals of Compressed Air Systems one-day training.Two instructors who have been screened and qualified by the CAC will teach the training session.

You will learn how to

  • calculate and reduce the costs of compressed air in your facility
  • how to gain better control of compressed air for optimum reliability and productivity
  • You’ll use data from your facility and complete hands-on exercises with emphasis on bottom-line results
  • Furthermore, you will know how to focus on getting results when you return to your plant

Materials, continental breakfast and lunch are included in the registration fee for this one day event.

Download Training Flyer

Register Today!

Compressed Air Best Practices: $215,000 Annual Savings Achievable

The most recent issue of Compressed Air Best Practices Magazine, the leading industry publication for facilities which rely on compressed air, features a case study which shows how an annual savings of $215,000 was achieved by Chicago Heights Steel. The payback time on the investment was less than 3 months while the savings will accrue annually for this specialty steel mill.

The investment includes a permanent, full-time state of the art monitoring system by Airleader which will ensure Chicago Heights Steel can continually monitor and maintain the system make adjustments and improve efficiency long after the air auditor has left. The system is easy for maintenance personnel to use and users can easily visualize what is taking place in the system through datalogging.

To read the feature article, click here: Compressed Air Best Practices Magazine, Chicago Heights Steel Saves $215,000 Annually.

Airleader Chicago Heights Steel

Airleader Saves Chicago Heights Steel 2.5 million kWh annually

Airleader Chicago Heights Steel

Chicago Heights Steel receives ComEd rebate


Airleader performed a complimentary leak study and leak repair. The service provider knew there were much greater energy savings to harvest through system improvements and persuaded a reluctant management to install a Master Controller to continuously monitor the system during operating hours and down time. By monitoring and analyzing key performance indicators with the Master Controller, improvements to increase the efficiency of the system were identified then verified. The project resulted in an overall decrease of 2,582,979 kWh annually or $215,037 at current rates. Additionally, the mill received a utility rebate in the amount of $177,714 which resulted in a simple Return on Investment of 0.2 years.

Airleader CHS Project Stats
The Project

Many industrial customers are frustrated with the high costs of their compressed air systems. Airleader was the third service provider contacted and performed a leak study and leak repair. The previous attempts were incomplete. Airleader provided a complimentary leak test and repair for the customer. After the complimentary leak repair the customer was not motivated to move forward with further measures doubting the savings would be worth the investment.

Airleader, on the other hand, knew there were much greater energy savings to harvest through system improvements and persuaded the customer to install a Master Controller to continuously monitor the system during operating hours and down time.

The System

The existing air system consisted of two compressor rooms which were not connected. There were three compressors in each room and two different system pressures. There were two desiccant dryers. The system was being manually controlled with 5 out of 6 compressors running in modulation.

The Pilot Audit/Permanent Monitoring System

Airleader Master Controller and Monitoring was set up providing continuous, online data logging during production and during down time. kW meters were placed on each compressor. Flow meters and Dew Point sensors were placed after each compressor room.

Airleader Compressor Room Layout

Compressor Room Layout

Permanent Monitoring

Data was collected on the system from December 2015 – February 2016 (1) to provide a baseline and a snap shot of the system. During February leaks were repaired. The first month of leak repair savings were harvested by the company in March (2). Airleader connected temporarily to one compressor room to verify saving potential (3). The next step was to replace the desiccant dryers with cycling dryers. (4) resulting in further savings.

The last week in December, the Airleader Master Controller was connected to the system. Maintenance was given access to online monitoring. A 4” pipe connecting the two compressor rooms was opened. Dramatic energy savings were achieved through system improvements (5). Because of the significant savings, the customer was able to invest new compressors to replace the compressors which were older than 20 years and not as reliable. A 200HP and 75HP VSD were installed as well as a 150HP fixed drive. Performance suffers based on 5-7% premium energy demand of the VSDs.

Airleader Compressor Energy Savings

Energy Savings Resulting from Project Improvements

Project Results

This project resulted in an overall decrease of 2,582,979 kWh or $215,037 which the customer will harvest annually. The total project costs for installing permanent monitoring and Master Controller, upgrades to system piping, storage and compressors were $240,139. The company received a $177,714 utility incentive. The project had a simple ROI of 0.2 year after utility incentives.

The key takeaway of this project is that the opportunities for improvements would not have been discovered without permanent monitoring in place. The case study demonstrates permanent monitoring of the compressed air system is a best practice resulting in annual savings. It provides key system data which is useful for system troubleshooting and discovering additional system efficiency which may be gained.


ComEd Chicago Heights Steel Case Study

Trulite receives energy incentive check for $147,428.

Canadian Glass Plant Optimizes Autoclave Compressed Air


Canadian Glass Plant Optimizes Autoclave Compressed Air

By Alan Brossault

The current compressed air system operates as two systems. The autoclave system uses 190 psi which consists of two 150 hp fixed speed air compressors that are used to pressurize the large autoclave vessel during the lamination process.  The plant side that operates at 110 psi to supply various manufacturing and lifting processes which uses a 150 hp variable speed compressor. One PRV is connected between the two systems which allows for higher pressure air to be supplied to the plant system via the PRV at 110 psi in the event the plant compressor needs repairs, etc.  In theory, this works well until the autoclave indexes which creates a huge draw of air which drains the system near the 75-80 PSI mark before recovering.  This in turn shuts down production equipment due to the minimum requirement being 95 psi to the plant processes.The Trulite Glass and Aluminum Solutions manufacturing plant in Ontario (Canada) manufacturers high end commercial glass products in its high tech production facility. The facility uses a large amount of electricity to manufacture laminated glass in the autoclave process.  This process is the largest consumer of compressed air in the facility which made compressed air a major target in reducing energy costs for the facility. As the volume of compressed air in the autoclave is significant, the system is constantly pressurized with large 150 HP air compressors to reduce production times and fill times of the autoclave.

Due to rising energy costs and problematic compressed air issues, a compressed air study was performed of the system identifying some major deficiencies within both the autoclave side, 190 psi high pressure [HP] system and the plant side 110 psi low pressure system [LP] system. The most obvious issues with the system were:

  • Lack of storage causing large pressure swings.
  • No control of the compressors causing excessive idling.
  • Grossly oversized plant VSD compressor on the lower pressure side of the system.


Low and High Pressure Compressed Air Systems

The low pressure system had no storage installed to buffer the oversized variable speed compressor which when combined with the load being less than the minimum output of the compressor caused large pressure swings. The compressor virtually operated in a load/no load manner starting and stopping constantly to try and maintain a steady pressure.

The high pressure system had one air receiver which was placed beside the autoclave to try and buffer the pressure swings caused by the filling of the vessel during the lamination process. The size of the receiver was not sufficient to stop the pressure from decaying beyond the clients needs during the initial fill which caused quality issues and alarms.

Secondary to the HP process issues caused by the lack of storage, the compressors ran inefficiently as they were always running unloaded to be ready to produce air and keep the pressure up. The idle times had been set to long and load/unload setpoints set so close that they could never stop and go into auto restart. The service provider explained to us that these settings were in place to try and keep the pressure up during various purge and process events in the autoclave, having the units off and restarting to provide the air requirement took to long to do so.


Typical autoclave system CFM trend over 24 hours showing large gaps between the cycle requirements.


 Pressure graph for autoclave cycle showing the decay of pressure due to the large draw of air.

Plant-Side VSD Air Compressor

Regardless of the path we chose for this system the 150hp VSD compressor that was ramping up and down to supply air to the plant system had to go. The plant load was well below the minimum for this compressors output which was causing drive issues due to the ramping as well as consuming much more energy than needed. Our analysis via the Airleader audit system provided us the information we needed to choose a correct size of machine. A 60hp VSD was chosen for the plant demand which would allow for some growth while providing the right amount of air in the best power curve of the VSD.


Specific Power charts from CAGI Data Sheets are very useful.

Compressed Air Storage


The plant side [LP] system was given storage to allow for 5 gallons/ cfm of air required and provide a smooth system for the VSD to trim.  On the autoclave side of the [HP] system we recommended tripling storage from 2560 to 7680 USG.  This allowed time for the compressors to respond when the autoclave began its large fill requirement.  Secondary to this, the new storage now allows the HP system to back-up the LP plant system without issues in pressure which is done via a regulator controlled from the Airleader master controller which regulates air to the plant side if the plant compressor should fail and the plant pressure gets to 95PSI. This also provided savings to the client by not having to bring in rentals for a compressor issue in the plant as well as eliminating the cost of purchasing a backup unit. With the previous system the storage was not enough on the HP system causing the pressure to decay to 75-80 psi before starting to recover during an autoclave cycle. Now that the system has more storage the pressure never decays below 100 psi allowing this air to be regulated to the plant side at 95psi eliminating need for the purchase of a backup compressor.


Old System

New System

Autoclave System

The autoclave system had many variables including the initial surge to fill the large autoclave vessel, some additional purge air, as well as varying requirements for variances in product.  Different products had very different pressure and flow requirements for compressed air. Knowing this information we knew right away a master controller was required if we wanted to stop compressors and choose the right compressors to fulfill the process.

After analysing the variances in product requirements via the Airleader software, along with information provided by the plant, we decided on a 60hp VFD to trim the cycle purges and work within the requirements of each product recipe. The existing two 150hp compressors would be used simply for the initial surge and one unit for a particular product that requires a secondary fill. Although a 60hp VFD trimming against a 150hp fixed speed would normally put the system into a large “control gap”, this process is unique in which a small VFD covers the complete process properly for leaks and short purges that require small amounts of air.  A large VFD would be below its minimum much like the old plant system VFD was. The client procured the compressors and tanks along with an Airleader master controller which was then implemented.

Once installation was completed Compressor Management Inc. took over the commissioning and setup of the system to operate as simulated by the Airleader software. The new system no longer runs the 150hp in constant idle to trim the purge on the autoclave and pressure issues have been eliminated. In fact, more than 90% of the time the two 150hp units are now stopped and off waiting for the Airleader Master Controller to give a start command when required resulting is secondary maintenance savings benefits. The client now watches his system from his desktop via the Airleader webserver and calls for assistance long before a breakdown or production is interrupted by a compressor problem.

Maintenance Manager John McGraw (far right), receives on behalf of Trulite, a $147,428 (CND) energy incentive check, for the compressed air retrofit project, from representatives of the local utility company.



System Summary

Now that the technical reviewers have completed the post analysis, the client has received the $147,428 CND incentive cheque for the project from the local utility supplier. The system now runs trouble free with online visualising of the whole system ensuring reliability and peace of mind while providing a total energy reduction of 83% which reduced the kWh’s by 2.3 million annually.

Annual KWH

Base case before project 2,824,522 kWh

New energy costs after project 481,122 kWh

Total annual savings for the client 2,343,400. kWh


For more information contact Alan Brossault at email: For more information on Airleader master controllers visit





Molex, Inc.’s Air Compressor Study

Molex, Inc. repiped their air compressor system, repaired air leaks, added a high-tech Airleader control system to monitor equipment electronically and also added a large compressed air storage tank. Since the 2007 audit, the facility’s average system airflow requirements have increased by approximately 43 percent. The retrofitted system has been capable of providing the additional airflow and the system operating cost is only 5 percent above the pre-retrofit cost.
Estimated Annual Savings of $93,856 (If plant airflow requirements had not increased)
  • Demand reduction 298 kW
  • Energy savings from reduced system operating pressures 742,000 kWh
  • Energy savings from repaired leaks 125,000 kWh
  • Energy savings from reduction of compressors 2,607,000 kWh

Screen Shot 2016-06-16 at 10.43.59 AM

Doug Badje and Randy Kaup of Molex, Inc.

The greatest benefits we’ve received since upgrading our compressed air system have been the savings of time and energy. In a one-half-million-square foot plant, being able to quickly identify where the system problem is located, the faster we

Also, we are now able to better monitor the system and save energy by recognizing which compressors to start and stop” said Randy Kaup, Molex Facilities Maintenance Supervisor
LES Smart Energy Form brings together experts in various aspects of energy conservation to provide commercial customers with opportunities to learn more about how to save money by saving energy.
The next forum is scheduled for September to discuss how customers can save energy and money with energy management systems. Please contact your LES account executive if you have any questions about the LES programs or incentives.

Compress Your Air Cost

Compressed air, often called the 4th utility, is one of the most expensive energy sources used in industrial plants, yet most plants have no reliable way to measure how efficient their compressed air systems are operating and how much it is costing them. In comparison, the owners of traditional utilities such as electricity, gas and water, have highly sophisticated systems in place to assure the demand and supply side match most efficiently.


ADA – Compressed air might not be what most manufacturers lose sleep over, but it is one area where waste can add up. The key to getting manufacturers to notice their compressed air operations is to show them what savings they could realize if they had more efficient systems, and that’s Jan Hoetzel’s job at SIGA Green Technologies.