Compressed air is one of the most useful utilities in an industrial facility, but producing it requires a significant amount of energy. More than 80% of the energy supplied to a compressed air system can be lost as heat, which makes system efficiency especially important for facilities trying to control operating costs.
The good news is that improving air compressor efficiency doesn't necessarily mean replacing your compressor.
The most effective ways to improve air compressor efficiency are to repair leaks, reduce unnecessary system pressure, keep up with preventative maintenance, match compressor output to actual demand, minimize pressure drop, improve intake conditions, and eliminate unnecessary uses of compressed air.
For many facilities, the biggest opportunities aren't found in the compressor itself. They're found by looking at how the entire compressed air system produces, distributes, and uses air.
What Is Air Compressor Efficiency?
Air compressor efficiency describes how effectively a compressed air system converts electrical energy into usable compressed air at the pressure and flow your facility actually needs.
An efficient system produces the required CFM and pressure without excessive energy consumption, pressure loss, unloaded runtime, or wasted compressed air.
That means compressor efficiency depends on more than the make and model of the compressor. It can also be affected by:
- Compressor sizing and controls
- Air leaks
- Operating pressure
- Filters and air treatment equipment
- Piping and distribution
- Storage capacity
- Intake conditions
- Maintenance
- How compressed air is used throughout the facility
If your system is consuming more electricity without a corresponding increase in production, one or more of these areas may be contributing to the problem.
8 Ways to Improve Air Compressor Efficiency
| Efficiency Opportunity | What to Look For | Potential Improvement |
|---|---|---|
| Air leaks | Hissing, pressure loss, unexplained demand | Repair and establish routine leak detection |
| System pressure | Pressure set higher than equipment requires | Reduce pressure to the lowest reliable setting |
| Maintenance | Dirty filters, worn parts, dirty coolers | Follow a preventative maintenance schedule |
| Compressor controls | Excess unloaded runtime or cycling | Optimize controls for actual demand |
| Compressor sizing | Compressor consistently over- or under-utilized | Evaluate sizing and demand profile |
| Piping | Excessive pressure drop or restrictions | Correct undersized or poorly designed piping |
| Intake conditions | Hot, dirty, or restricted inlet air | Improve ventilation and intake airflow |
| End uses | Air used for cooling, cleaning, or blowing | Replace inappropriate uses where practical |
1. Find and Repair Compressed Air Leaks
Air compressor leaks should be one of the first places you look when trying to improve compressed air efficiency.
According to the U.S. Department of Energy, leaks in a poorly maintained compressed air system can waste 20–30% of the compressor's output. A well-maintained system, by comparison, can reduce leakage to less than 10% of compressor output.
Common leak locations include:
- Couplings
- Hoses and tubing
- Fittings
- Pipe joints
- Quick disconnects
- Pressure regulators
- Condensate traps
- Shut-off valves
Leaks don't just waste compressed air. They can lower system pressure and force compressors to run longer to maintain production requirements.
Large leaks may be audible during a plant walkthrough, but smaller leaks can be difficult to locate in a noisy manufacturing environment. Ultrasonic leak detection can help identify leaks that would otherwise go unnoticed.
Leak repair also shouldn't be a one-time project. Establishing a routine leak detection, tagging, repair, and verification program helps prevent system losses from gradually returning.
2. Operate at the Lowest Pressure Your Facility Actually Needs
Higher pressure requires more energy to produce. It can also increase the amount of air lost through existing leaks and unregulated end uses.
That makes unnecessarily high system pressure a double source of wasted energy.
However, don't automatically lower compressor pressure without evaluating the entire system first. Your equipment still needs enough pressure to operate reliably at the point of use.
If one area of the facility isn't getting enough pressure, increasing compressor discharge pressure may simply mask another problem, such as:
- Undersized piping
- Clogged filters
- Restrictions
- Insufficient storage
- Poor distribution design
- High intermittent demand
The goal is to identify the lowest system pressure that reliably supports production, rather than compensating for distribution problems by generating higher pressure at the compressor.
3. Keep Up With Preventative Air Compressor Maintenance
An air compressor can continue running even when its efficiency is gradually declining.
Dirty filters, degraded lubricant, worn components, clogged coolers, and other maintenance issues can increase pressure drop, operating temperatures, and energy consumption long before they cause a complete system failure.
Maintenance items that can affect air compressor efficiency include:
- Air and oil filters
- Air/oil separators
- Lubricant condition and level
- Belts and couplings
- Coolers
- Condensate drains
- Intake filters
- Valves and controls
Following the manufacturer's recommended service intervals helps keep these components operating as intended.
TMI offers preventative maintenance for all makes and models of compressed air systems. Our factory-trained technicians can identify developing issues before they become larger efficiency, reliability, or downtime problems.
4. Match Compressor Output to Your Actual Air Demand
A compressor is most efficient when its capacity and control strategy fit the facility's actual demand profile.
An oversized compressor isn't automatically better. If the unit regularly produces far more air than the facility needs, it may spend excessive time unloaded or cycle frequently.
A variable speed drive (VSD) compressor can be useful when compressed air demand changes significantly throughout the day. Instead of operating at one fixed motor speed, a VSD compressor adjusts its output as demand changes.
However, a VSD isn't automatically the most efficient choice for every facility.
Plants with relatively stable demand may be better served by another compressor and control strategy. Facilities with multiple compressors also need to consider how those machines interact rather than evaluating each compressor independently.
Before replacing equipment, review your facility's actual CFM demand across shifts and production conditions. That data can help determine the appropriate compressor size and control strategy.
5. Reduce Pressure Drop Throughout the System
Your compressor may be producing enough pressure while your equipment still isn't receiving it.
Pressure can be lost as compressed air moves through filters, dryers, piping, fittings, valves, hoses, and other components. Excessive pressure drop often causes facilities to increase compressor discharge pressure to compensate — increasing energy consumption instead of addressing the restriction.
Potential causes of pressure drop include:
- Dirty or undersized filters
- Undersized piping
- Long piping runs
- Too many fittings or sharp turns
- Poor piping layout
- Undersized hoses or connectors
- Improperly sized air treatment equipment
Measure pressure at multiple points throughout the system rather than relying exclusively on the compressor's discharge pressure.
If pressure is adequate in the compressor room but significantly lower at critical equipment, the distribution system may be where the efficiency problem is occurring.
6. Give Your Compressor Clean, Cool Intake Air
Intake conditions can affect compressor performance.
Hot intake air is less dense than cooler air, while dirty or restricted intake air makes it harder for the compressor to draw in the air it needs.
Rather than simply moving a compressor to the coldest part of the facility, make sure the compressor room and intake system provide adequate ventilation and access to clean, reasonably cool air within the equipment manufacturer's specifications.
Keep intake filters clean and make sure ventilation systems aren't allowing hot compressor exhaust air to recirculate back into the intake.
This can improve compressor operating conditions while also helping prevent overheating.
7. Eliminate Inappropriate Uses of Compressed Air
Sometimes the easiest way to improve air compressor efficiency is to require the compressor to produce less air.
Compressed air is convenient, but it isn't always the most efficient energy source for a particular application.
Review your facility for compressed air being used for jobs such as:
- Open blowing
- Cleaning work areas
- Cooling products or equipment
- Drying
- Personal cooling
- Vacuum generation
Depending on the application, engineered nozzles, blowers, fans, electric tools, or dedicated vacuum systems may be able to perform the same job while reducing compressed air demand.
Reducing unnecessary demand can also create additional capacity in your existing system, potentially delaying the need to purchase another compressor.
8. Monitor and Optimize the Entire Compressed Air System
You can't optimize what you aren't measuring.
A compressed air system audit can reveal problems that aren't obvious during normal operation. Instead of evaluating only the compressor, an audit looks at how air is generated, treated, stored, distributed, and consumed throughout your facility.
Useful measurements can include:
- Compressor power consumption
- CFM demand
- System pressure
- Pressure drop
- Loaded and unloaded runtime
- Demand by shift
- Compressor sequencing
- Leak load
This information can help determine whether your biggest opportunity is repairing leaks, changing control settings, lowering pressure, modifying piping, adding storage, improving maintenance, or replacing equipment.
TMI's compressed air audits evaluate the complete system and use operating data to identify efficiency opportunities. Recommendations can then be modeled against current system performance to estimate potential energy and cost savings before you invest in improvements.
Should You Replace Your Air Compressor to Improve Efficiency?
Not necessarily.
If your compressor is consuming too much energy, replacing it before identifying the underlying problem could leave many of the same inefficiencies in place.
For example, a new high-efficiency compressor will still waste energy if your facility has significant air leaks, excessive system pressure, poor piping, or unnecessary compressed air demand.
Replacement may make sense when a compressor is:
- Incorrectly sized for current demand
- Nearing the end of its useful life
- Requiring increasingly frequent repairs
- Unable to efficiently respond to your facility's demand profile
- Significantly less efficient than available equipment
A system assessment can help determine whether replacing the compressor or optimizing the existing system will provide the better return.
How Do You Know If Your Air Compressor Is Running Efficiently?
Start by comparing the amount of compressed air your facility actually needs with the energy required to produce it.
Warning signs of an inefficient compressed air system can include:
- Increasing electricity costs without increased production
- Compressors running when production equipment is idle
- Frequent loading and unloading
- Significant pressure differences across the system
- Constantly increasing discharge pressure
- Frequent air leaks
- Higher-than-normal operating temperatures
- Multiple compressors running when fewer should meet demand
These symptoms don't automatically mean the compressor itself is inefficient. They indicate that the complete system should be evaluated to determine where energy is being lost.
Air Compressor Efficiency FAQs
What is the most common cause of compressed air energy waste?
Air leaks are one of the most common sources of wasted compressed air. In poorly maintained systems, leaks can account for 20–30% of compressor output. Regular leak detection and repair can significantly reduce unnecessary demand.
Does lowering air compressor pressure save energy?
It can. Producing higher-pressure compressed air requires more energy, so operating at the lowest pressure that reliably supports your equipment can improve system efficiency. Pressure should be reduced carefully, however, because insufficient pressure can affect production.
Are variable speed air compressors more efficient?
Variable speed drive compressors can be highly efficient in facilities where compressed air demand fluctuates. They aren't automatically the best option for every application, though. Compressor selection should be based on the facility's actual demand profile and operating conditions.
How often should compressed air leaks be checked?
Leak detection should be an ongoing maintenance activity rather than a one-time project. How frequently your facility needs a full leak survey depends on the size of the system, operating environment, production schedule, and historical leak rate.
Can a compressed air audit lower energy costs?
A compressed air audit can identify where energy is being wasted and quantify opportunities for improvement. Audits can uncover leaks, excessive pressure, inefficient compressor sequencing, pressure drop, inappropriate air uses, and equipment that isn't properly matched to demand.
Improve Air Compressor Efficiency by Looking at the Whole System
Improving air compressor efficiency isn't about finding one setting or replacing one component. The best results come from looking at the compressed air system as a whole.
Start with the fundamentals: repair leaks, use the lowest reliable system pressure, maintain your equipment, reduce unnecessary demand, and make sure compressor capacity and controls match the way your facility actually operates.
If you don't know where your biggest efficiency losses are occurring, measure before you invest.
TMI Compressed Air Systems can evaluate your compressors, controls, air treatment equipment, piping, storage, and end uses to identify opportunities to improve performance and reduce energy costs. From compressed air audits and system optimization to preventative maintenance and equipment upgrades, we'll help you determine which improvements make sense for your facility.
Ready to find out where your compressed air system could be more efficient? Request a compressed air system evaluation from TMI.
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