23 – 29 kW screw compressors
A step up in flow without moving to a larger plant room.
Technical data
- Free air delivery
- 0.9 – 5.5 m³/min
- Working pressure
- 8 – 13 bar g
- Motor power
- 22 – 30 kW
- Weight
- 650 – 712 kg
- Noise level
- 67 – 69 dB(A)

Overview
This narrow band exists because a lot of growing plants outrun a 22 kW machine but do not have the electrical supply or the floor space for a 37 kW one. Rather than force you into an oversized machine that spends its life unloaded, we build the sizes in between.
Mechanically these units share the airend family of the 30 – 45 kW range, so parts, service intervals and workshop familiarity carry straight across if you later add a bigger machine.
Key benefits
Bridges the gap
Fills the step between a 22 kW and a 37 kW machine so you buy capacity you will actually use.
Same parts as the bigger range
Shared filters, separators and oil with the 30 – 45 kW units: one spares shelf covers both.
Sequencing ready
Built-in controller can run as master over up to five other Green Air machines without an external panel.
How it is built
This band exists for the plant that has outgrown a twenty two kilowatt machine but has neither the electrical supply nor the floor space for a thirty seven. Mechanically it shares the airend family of the larger machines, so parts, intervals and workshop knowledge all carry across.
The cooler and the fan are sized for the same ambient as the bigger units rather than being carried over from the smaller ones. That is the part suppliers usually economise on, and it is the part that decides whether the machine runs through a Gulf summer.
The frame, the mounts and the canopy are common with the thirty to forty five kilowatt range, which keeps spare panels, filters and seals on one shelf instead of two.
- Airend family shared with the larger range
- Cooler sized for high ambient temperatures
- Common frame and canopy with 30 to 45 kW
- Low vibration, no special foundation
- Star delta starting as standard
- Variable speed available
- Air cooled or water cooled
- Service points on one side
What the controller does
The same controller as the larger plant room machines, so an engineer who knows one knows all of them. Pressure, load, hours and the service countdown sit on the home screen and the rest is one level down.
Trend graphs are the part operators actually use. Watching discharge temperature and load percentage over weeks is how a bearing starting to warm up gets found while it is still a service rather than an airend.
Remote monitoring is fitted and free for the first three years. Alerts reach you and the engineer who covers your area at the same time, which is usually how a problem gets caught before it becomes a stoppage.
- Same controller as the larger machines
- Pressure, load, hours and service countdown
- Trend graphs for temperature and load
- Sequencing with other units
- Scheduled start and stop
- Remote monitoring free for three years
- Automatic restart after a power failure
- Fault history kept on the machine
Parts and service kits
Kits follow the same intervals as the larger plant room machines. Consumables at two thousand hours, separator and oil at four thousand, and the full performance check at eight thousand.
Because the airend family is shared, so are most of the wear parts. A workshop that already stocks for a thirty seven kilowatt machine is close to stocking for this one as well.
We confirm every kit against the serial number before it ships. Air cooled and water cooled builds take different parts, and a model number on its own does not tell us which one is standing in your plant room.
- Consumables at two thousand hours
- Separator and oil at four thousand
- Full performance check at eight thousand
- Wear parts shared with the larger range
- Confirmed against your serial number
- Genuine fluid to the tested specification
- Local stock, not a lead time
- Fixed price on a service plan
Model range
Fixed speed
- 7.5 bar g
- 4.16 m³/min
- 10 bar g
- 3.45 m³/min
- 13 bar g
- 2.98 m³/min
- Noise level
- 67 dB(A)
- Weight
- 650 kg
- Dimensions L x W x H
- 1345 × 880 × 1612 mm
- 7.5 bar g
- 4.84 m³/min
- 10 bar g
- 4.13 m³/min
- 13 bar g
- 3.44 m³/min
- Noise level
- 68 dB(A)
- Weight
- 677 kg
- Dimensions L x W x H
- 1345 × 880 × 1612 mm
- 7.5 bar g
- 5.52 m³/min
- 10 bar g
- 4.81 m³/min
- 13 bar g
- 4.12 m³/min
- Noise level
- 69 dB(A)
- Weight
- 681 kg
- Dimensions L x W x H
- 1345 × 880 × 1612 mm
Variable speed
- 7.5 bar g
- 1.11 – 4.12 m³/min
- 10 bar g
- 1.03 – 3.70 m³/min
- Noise level
- 68 dB(A)
- Weight
- 681 kg
- Dimensions L x W x H
- 1345 × 880 × 1612 mm
- 7.5 bar g
- 1.11 – 4.78 m³/min
- 10 bar g
- 1.03 – 4.10 m³/min
- 13 bar g
- 0.92 – 3.56 m³/min
- Noise level
- 69 dB(A)
- Weight
- 708 kg
- Dimensions L x W x H
- 1345 × 880 × 1612 mm
- 7.5 bar g
- 1.11 – 5.41 m³/min
- 10 bar g
- 1.03 – 4.50 m³/min
- 13 bar g
- 0.92 – 3.82 m³/min
- Noise level
- 69 dB(A)
- Weight
- 712 kg
- Dimensions L x W x H
- 1345 × 880 × 1612 mm
FAD measured to ISO 1217 Edition 4, Annex C and E at 1 bar a intake, 20°C, 0% humidity. Noise measured to ISO 2151 in free field conditions, tolerance ± 3 dB(A). Water-cooled versions of every model are available. Ask us for their sheet.
Frequently asked questions
Why does this narrow band exist?
Because plants outgrow a 22 kW machine long before they have the electrical supply or floor space for a 37 kW one. Buying the next size up means paying for capacity you will not use.
What happens if I just buy the 37 kW instead?
It will spend most of its life unloaded, drawing 25–35% of full power for no air. Over ten years that costs far more than the price difference between the two machines.
Do these share parts with the larger range?
Yes. Filters, separators and oil are common with the 30–45 kW machines, so one spares shelf covers both if you later add a bigger unit.
Can it act as the lead machine for others?
Yes, the built-in controller sequences up to five other Green Air machines without an external panel, and rotates the lead so they age evenly.
How much air do I get?
About 4.1 m³/min (145 cfm) at 25 kW and 4.8 m³/min (170 cfm) at 29 kW, both at 8 bar.
Is the variable speed version available in this band?
Yes, covering 1.2–4.9 m³/min from 5 to 13 bar. It is often the right answer here because plants in this band are usually growing and demand is not settled.
What does it need electrically?
Three phase with star-delta starting. The starting current is well within what most existing 37 kW supplies can handle, which matters if you are replacing an older machine.
How much space does it need?
About the same footprint as the 22 kW, with one metre of clear access on the service side. Ventilation matters more than floor area at this size.
Can I add a second machine later?
Yes, and sequencing is already built in. Adding a smaller variable speed machine to trim while this one carries base load is the usual next step.
What is the service interval?
The same schedule as the rest of the screw range: 2,000, 4,000 and 8,000 hours, with airend assessment at 40,000.
Related products

Direct driven screw compressors
Motor coupled straight to the airend. 55 to 250 kW, nothing to slip.
- Free air delivery
- 7.8 – 43.0 m³/min
- Working pressure
- 7 – 13 bar g
- Motor power
- 55 – 250 kW

Variable speed screw compressors
The motor follows the demand. 7.5 to 280 kW, 8 to 13 bar g.
- Free air delivery
- 0.3 – 50.0 m³/min
- Working pressure
- 8 – 13 bar g
- Motor power
- 8 – 280 kW

Two stage screw compressors
Compression in two steps. 45 to 500 hp, 4.5 to 12.5 bar g.
- Free air delivery
- 6.6 – 101.3 m³/min
- Working pressure
- 5 – 13 bar g
- Motor power
- 45 – 355 kW

Permanent magnet screw compressors
IE4 and IE5 class motors with variable speed built in. 20 to 500 hp.
- Free air delivery
- 0.3 – 109.0 m³/min
- Working pressure
- 7 – 30 bar g
- Motor power
- 8 – 55 kW
Not sure which model you need?
Send us your air demand, working pressure and running hours. Our engineers will size the machine and send a written recommendation, no cost, no obligation.