2025 Air Compressor Industry Trend: PM VFD vs. Regular VFD - How Big Is the Energy-Saving Gap?

In 2025, with the implementation of the "Motor Energy Efficiency Improvement Plan (2023-2025)", the tightening of global carbon footprint standards, and the soaring demand for high-efficiency compressed air in emerging industries such as new energy vehicles and semiconductors, the air compressor industry is ushering in a critical transition period centered on "energy conservation as king". Among them, the "energy-saving dispute" between permanent magnet variable frequency (PM VFD) and regular variable frequency models has become the core focus of enterprise selection - the market penetration rate of the former has jumped from less than 25% in 2020 to 58% in 2025, while the latter is gradually facing the risk of elimination due to "failure to meet energy efficiency standards". Combining industry data and technical principles, this article analyzes the energy-saving gap between the two types of models to provide reference for enterprises' selection in 2025.

I. First, Understand the Core Difference: Motor Technology Determines the "Foundation" of Energy Conservation

The energy-saving gap between PM VFD and regular VFD air compressors essentially stems from the efficiency gap caused by the generational gap in motor technology. Although both types of models adopt the "variable frequency speed regulation" logic, the design of their core power component - the motor - is completely different, which directly determines the lower limit of energy consumption:

Taking the actual test data of Qisheng Intelligent Equipment as an example: when a 110kW model operates at 50Hz (full load), the PM VFD consumes 5.5 kWh less per hour than the regular VFD; when the load drops to 50% (30Hz), the efficiency of the regular VFD drops to 82%, while the PM VFD still maintains 92%, and the hourly power saving gap expands to 11 kWh - which is equivalent to an additional electricity cost of about 20,000 yuan per year (based on 300 operating days and an industrial electricity price of 1 yuan per kWh).

II. Analysis from Four Dimensions: Where Exactly Does PM VFD Save More Than Regular VFD?

In addition to the efficiency difference of the motor itself, PM VFD further widens the energy-saving advantage through the whole-process optimization of "load adaptation, start-stop control, and pressure regulation". The specific energy savings can be quantified from 4 core scenarios:

1. Load Fluctuation Scenario: The Energy-Saving Gap Expands with Fluctuation Amplitude, Up to 40%

The actual air consumption of enterprise air compressors is often only 50%-70% of the rated displacement (15%-25% margin is reserved during selection), and this "load fluctuation" is exactly the advantage scenario of PM VFD.

According to the working condition test of Unite: for a 37KW (6 cubic meters) model under the daily working condition of "5 hours of full load + 3 hours of low load (30%)":

• Regular VFD air compressor: 35kW power consumption at full load; due to the efficiency decline of the asynchronous motor at low load, the power consumption still reaches 28kW; daily power consumption = (35×5) + (28×3) = 259 kWh;

• PM VFD air compressor: 32kW power consumption at full load; stable efficiency at low load, power consumption is only 16kW; daily power consumption = (32×5) + (16×3) = 208 kWh;

Daily power saving of 51 kWh, annual power saving of 15,300 kWh, and energy-saving rate of 20%.

If the workshop air consumption fluctuates more (such as automobile maintenance and electronic assembly), the "inefficient idling" problem of regular VFD is more prominent, and the energy-saving rate of PM VFD can be further increased to 30%-40%.

2. Unloading Scenario: Regular VFD "Consumes Power During Idling", PM VFD Has Near-Zero Loss

When "air supply is excessive", traditional regular VFD air compressors will reduce frequency but cannot stop completely; they still need to maintain the main engine idling, consuming 30%-40% of the rated power. However, PM VFD can achieve true "stop when there is no air demand" through the "zero-speed sleep" technology.

Taking the actual test data of Bolaite as an example: a 37KW regular VFD consumes 18kW during unloading, while a PM VFD only consumes 3-3.5kW during unloading - saving 14.5-15 kWh per hour. If the workshop is unloaded for 3 hours a day, the annual power saving can reach 13,000-13,500 kWh.

3. Startup Scenario: Regular VFD "High Current Impact", PM VFD Soft Startup Without Waste

When a regular VFD air compressor (asynchronous motor) starts, although it is gentler than a power frequency machine, the starting current still reaches 3-4 times the rated current; while PM VFD adopts "soft startup", the starting current is only 1.2 times the rated current, and there is no frequent start-stop loss.

The power grid monitoring of a machinery factory shows that when the workshop starts 3 55KW regular VFD machines at the same time, the instantaneous current peak reaches 600A, causing power grid voltage fluctuation; after replacing with PM VFD machines, the starting current peak is only 200A, which not only avoids power grid impact but also reduces the additional electrical energy loss caused by "high current startup" - saving about 8,000 yuan in electricity costs annually due to startup loss.

4. Pressure Control Scenario: PM VFD "No Pressure Band Loss", Saving 1% Energy Consumption for Every 0.14Bar Reduction

To avoid frequent start-stop, regular VFD air compressors need to set a "pressure band" of about 1Bar (for example, set to 7-8Bar, but actually use 7Bar); the extra 1Bar pressure is completely "useless energy consumption". However, PM VFD can achieve "constant pressure point control" without reserving a pressure band, and directly supply air according to the actual demand (such as 7Bar).

According to the calculation of Unicoil Compressor:for every 0.14Bar reduction in pressure band, the system energy consumption can be reduced by 1%. If the actual pressure required by the workshop is 7Bar, the regular VFD needs to supply 8Bar, and the pressure loss alone consumes 7% more electrical energy; while the PM VFD directly supplies 7Bar, completely avoiding this part of waste - a 110kW model can save up to 55,000 kWh of electricity annually.

III. Choosing PM VFD in 2025: Not Just "Energy Saving", But Also "Compliance and Adaptation"

In 2025, enterprises' choice of PM VFD has long exceeded the single demand of "saving electricity costs", but is also an inevitable choice to respond to policies and adapt to emerging industries:

1. Policy Impetus: Models Failing to Meet Energy Efficiency Standards Will Be Eliminated, PM VFD Is the "Compliance Bottom Line"

Starting from 2025, the revised version of China's GB 19153 standard will increase the minimum energy efficiency limit of air compressors by 10%, and the EU ERP directive will require a further 8% increase in the energy efficiency of screw air compressors. Regular VFD air compressors (IE3/IE4 class motors) are already close to the energy efficiency red line, while the energy efficiency of PM VFD (IE5 class motors) is 20%-30% higher than that of regular VFD, fully meeting the policy requirements for the next 3-5 years.

A total of 10 regular VFD machines purchased by an auto parts factory in 2024 failed to pass the environmental protection acceptance in 2025 due to failure to meet energy efficiency standards, and had to invest an additional 500,000 yuan to replace them with PM VFD machines - choosing PM VFD in advance is equivalent to avoiding the cost of "secondary transformation".

2. Demand from Emerging Industries: PM VFD Is a "Necessity" for High-End Scenarios

Emerging industries such as new energy vehicles, semiconductors, and lithium batteries have extremely high requirements for the "stability and low energy consumption" of compressed air:

• Semiconductor manufacturing requires 24-hour stable air supply from air compressors with a pressure fluctuation ≤0.1Bar, which cannot be met by the pressure band of regular VFD, while the constant pressure control accuracy of PM VFD can reach ±0.05Bar;

• The daily operation time of a lithium battery production workshop is 16 hours; a PM VFD can save up to 30,000 kWh of electricity per year compared with a regular VFD. Calculated based on 10 units in the workshop, the annual electricity cost saving is 300,000 yuan, and the equipment price difference can be recovered in 2-3 years (data from Unite shows that the investment difference between PM VFD and regular VFD can be recovered in about 1 year).

3. Intelligent Adaptation: PM VFD Is the Core Entrance of "Intelligent Air Compressor Station"

It is expected that 1.2 million air compressors will be connected to the industrial Internet platform in 2025. Due to the high motor control accuracy and strong data collection capability, PM VFD can be directly connected to the cloud platform to realize "predictive maintenance and energy efficiency optimization". For example:

• By real-time monitoring more than 20 parameters such as motor speed and current, early warning of bearing wear can be realized (regular VFD can only monitor pressure and temperature);

• The cloud platform can automatically adjust the operation strategy of multiple PM VFD machines according to changes in air consumption, saving an additional 8%-10% energy compared with manual scheduling - this is impossible to achieve with the "extensive control" of regular VFD.

IV. Selection Suggestions: In 2025, Which Scenarios Prioritize PM VFD?

Combining industry trends and actual working conditions, PM VFD air compressors are recommended for the following scenarios in 2025, while regular VFD is only suitable for low-load and stable working conditions:

Conclusion: In 2025, PM VFD Is Not a "Choice", But a "Must"

From the cost advantage of "energy-saving gap of over 30%" to the strategic value of "policy compliance and high-end adaptation", PM VFD air compressors have changed from an "upgrade option" to a "basic configuration" for enterprises in 2025. For enterprises pursuing cost reduction and efficiency improvement and laying out emerging industries, choosing PM VFD is not only about saving electricity costs, but also about seizing the "energy efficiency high ground" in the future manufacturing competition.

As a provider of air compressor system solutions, Huitong Xinda can provide the whole-process service of "selection calculation + installation and commissioning + intelligent operation and maintenance" of PM VFD air compressors according to the enterprise's workshop scale, air consumption working conditions, and industry standards. At present, we have customized energy-saving solutions for more than 300 manufacturing enterprises, helping customers achieve an average energy consumption reduction of 25%. If you want to calculate the energy-saving potential of replacing PM VFD machines in your workshop, please feel free to contact us to obtain an exclusive energy efficiency evaluation report!