5 Signs Your Air Compressor Is Undersized

An undersized air compressor is one of the most common causes of poor performance, pressure loss, and rising operating costs in workshop environments.

Many workshops operate with insufficient CFM capacity without realising that their system is already limiting productivity and increasing wear on equipment.

1. Constant Pressure Drops During Operation

If air pressure drops when multiple tools are in use, your compressor may not be supplying enough CFM (cubic feet per minute) to meet demand.

This is one of the earliest and most common signs of an undersized system.

How to calculate CFM for a workshop

2. Compressor Running Continuously or Overcycling

If your compressor rarely shuts off, it is likely operating beyond its intended capacity.

This leads to:

• overheating

• increased wear and tear

• higher maintenance frequency

• shorter equipment lifespan.

3. Air Tools Losing Power or Efficiency

Undersized compressors cannot maintain consistent airflow, which affects tool performance.

• Common signs include:

• impact wrenches losing torque

• tyre equipment slowing down

• inconsistent operation across bays

This directly impacts technician efficiency and job turnaround time.

4. Increasing Electricity Costs Without Clear Cause

When compressors are undersized, they run longer and harder to meet demand.

This results in:

• excessive energy consumption

• higher electricity bills

• reduced system efficiency

5. Moisture Build-Up in Air Lines

Undersized systems struggle to manage airflow and cooling effectively, leading to:

• moisture accumulation

• contamination in air lines

• reduced tool lifespan

• potential damage to equipment

What to Do If Your Air Compressor Is Undersized?

Addressing an undersized system requires more than just replacing equipment.

Depending on your setup, solutions may include:

• upgrading to a properly sized compressor

• installing an additional air receiver

• redesigning pipework for better airflow

• optimising system layout and distribution

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FREQUENTLY ASKED QUESTIONS

• Can I just add another compressor?

  Yes, but only after assessing load requirements and system design.

• Does pipe size affect compressor performance?

  Yes. Improper air line sizing causes pressure drops.

• What CFM should a workshop air compressor have?

  The required CFM depends on the total demand of all air tools operating simultaneously, including peak usage. A proper assessment should account for tool specifications, duty cycles, and future expansion to avoid undersizing the system

• What happens if an air compressor is too small for the application?

  What happens if an air compressor is too small for the application?

• How does receiver tank size affect compressor performance?

  A properly sized air receiver helps stabilise pressure, reduce compressor cycling, and handle peak demand. Without adequate storage, the compressor may appear undersized even if capacity is technically sufficient.

• Can pipework design impact perceived compressor capacity?

  Yes. Poor pipe layout, undersized piping, and excessive bends can create pressure drops, making the system behave as if the compressor is undersized, even when capacity is adequate.

• Is a rotary screw compressor better for high-demand workshops?

  Rotary screw compressors are typically more suitable for continuous, high-demand environments as they provide consistent airflow, improved efficiency, and reduced pressure fluctuations compared to piston compressors.

If your workshop is experiencing pressure issues or inconsistent tool performance, it may be worth assessing whether your system is correctly sized.
Speak with our team to review your compressed air setup.