Why Is Compressed Air So Expensive?

Compressed air is expensive mainly because it requires significant energy to produce. Energy costs account for 70-80% of the total lifetime expense of a compressed air system.

This “fourth utility” in manufacturing facilities often goes unnoticed on balance sheets – despite being 7-8 times more expensive than electricity on a per-unit basis.

In this guide, we explore the key factors that make compressed air so costly. We’ll then cover practical ways to reduce these expenses and boost your bottom line.

The True Cost of Compressed Air Production

The production of compressed air requires converting electrical energy into potential energy stored as pressurized air – and this conversion process is inherently inefficient.

For every dollar spent on electricity to power an air compressor, only about 10-15 cents of useful energy is delivered as compressed air. The rest is lost as heat during the compression process.

On average, it costs around $0.25-$0.30 to produce 1,000 cubic feet of compressed air. While this might not sound significant, these costs quickly add up in industrial settings where compressed air systems run continuously.

The initial purchase price of compressor equipment only accounts for 10-15% of the total lifetime cost. Energy consumption makes up the vast majority at 70-80%, with maintenance making up the remaining 10-15%.

Many companies focus exclusively on the upfront capital expenditure when purchasing compressed air systems, overlooking the much higher long-term operational expenses.

A more accurate assessment would consider the total cost of ownership over the equipment’s expected lifetime (typically 10-15 years). When viewed this way, energy efficiency becomes the most critical factor in determining the true cost of a compressed air system.

Energy Inefficiency: The Primary Cost Driver of Compressed Air

Up to 90% of the electrical energy used to power air compressors is converted to heat. Without heat recovery systems, this thermal energy simply dissipates into the atmosphere.

The inefficiency extends beyond the compression process itself – system pressure plays a crucial role in energy consumption. Increasing system pressure by just 1 bar (14.5 psi) requires approximately 8% more power from the compressor.

Many facilities operate their compressed air systems at higher pressures than necessary for their applications. This common practice significantly increases energy costs without providing meaningful benefits.

Variable demand patterns further compound the inefficiency problem. Fixed-speed compressors running at partial loads consume disproportionately more energy relative to their output.

For example, a fixed-speed compressor operating at 50% capacity might still consume 80% of its full-load energy. This poor part-load efficiency explains why many compressed air systems are so expensive to operate.

The Hidden Costs of Compressed Air Leaks

Leakage is debatably the most wasteful aspect of compressed air systems. Up to 50% of compressed air produced in industrial facilities is often lost through leaks in the distribution system.

A single 1/8-inch diameter leak at 100 psi can cost more than $1,200 per year in wasted energy. Over time, even small leaks create substantial financial drain.

Air leaks can increase energy costs for compressed air systems by 30% or more. A leak as small as 1 CFM (cubic foot per minute) costs approximately $35 per shift annually.

These leaks occur throughout the system, particularly at:

• Pipe joints
• Connections
• Fittings, hoses
• Couplings
• Worn equipment

The cumulative effect creates a constant drain on system efficiency.

Worse yet, compressed air leaks often go undetected for quite a while. Unlike water or oil leaks that leave visible evidence, air leaks are invisible and sometimes difficult to hear in noisy industrial environments.

Cost-Effective Strategies for Reducing Compressed Air Expenses

To mitigate the inherent inefficiencies of compressed air, you can use several strategies like:

• Implementing leak detection: a comprehensive leak detection and repair program can significantly reduce compressed air costs. Ultrasonic leak detection equipment can identify leaks that would otherwise remain hidden, enabling targeted repairs that quickly pay for themselves through energy savings.
• Using VSD compressors: variable speed drive (VSD) compressors offer dramatic improvements for applications with fluctuating demand. These systems can reduce energy consumption by up to 70% compared to fixed-speed compressors by matching output precisely to demand.
• Leveraging heat recovery: heat recovery systems capture the thermal energy produced during compression. This recovered heat can be used for space heating, water heating, or process applications, effectively getting double duty from the energy consumed.
• Reducing system pressure: pressure reduction is a major cost-cutting opportunity. Reducing system pressure by just 0.5 bar (7.25 psi) can result in energy savings of about 3.5%. Most facilities can lower their operating pressure without affecting performance.
• Auditing your systems: regular system audits help identify opportunities for cost-effectiveness improvements. Professional compressed air audits typically identify energy savings of 30-50% with payback periods of less than two years.

Besides these strategies, regular maintenance is crucial for optimal efficiency. Clean intake filters, proper lubrication, and belt tension adjustments help compressors operate at peak performance with minimal energy waste.

Finally, replacing compressed air with more efficient alternatives for certain applications can yield substantial savings. Electric tools, blowers for cooling or drying, and mechanical methods often perform the same functions at a fraction of the energy cost.

Making Informed Decisions About Compressed Air

Understanding the true cost of compressed air is essential for making data-driven business decisions about its use. The convenience and versatility of compressed air come with significant financial implications.

When evaluating compressed air systems, focus on energy efficiency instead of just the initial purchase price. The most expensive compressor to buy might be the least expensive to own over its lifetime if it offers superior efficiency.

Consider the appropriate quality level for each application. Producing higher quality compressed air (drier, cleaner, oil-free) requires more energy and more expensive equipment, so match the air quality to the actual requirements.

By understanding all the cost drivers of compressed air and implementing targeted efficiency measures, you can significantly reduce the related expenses while maintaining its benefits for appropriate applications.