Axial vs. Centrifugal Fans
How to Choose the Right One for Your Facility
Axial or centrifugal? The answer depends on your system's resistance.
Both fan types move air, but they do it using different mechanical principles. Choosing the right one means matching the physics of the fan to the pressure demands of your environment, and getting it wrong costs you in energy, maintenance, and performance.
This decision impacts your initial budget, long-term energy costs, and maintenance schedules. While both designs are built to move air, they do so using very different mechanical principles. Choosing the right one is about matching the physics of the fan to the specific resistance of your environment.
How Each Fan Type Works
To make the right choice, it helps to visualize how the air travels through the equipment.
Axial Fans: The Straight Path
An axial fan moves air parallel to the shaft around which the blades rotate. The air is pulled in straight and pushed out straight. Because the flow is direct, these fans are highly efficient at moving large volumes of air (CFM) at low resistance. However, their performance can drop off quickly if they encounter significant static pressure.
Centrifugal Fans: The Right Angle
Commonly known as blowers, centrifugal fans work by drawing air into the intake and turning it 90 degrees before accelerating it radially. This change in direction and the use of centrifugal force allows these fans to generate much higher pressure. This makes them the standard choice for moving air through filters, dampers, or extensive ductwork.
The Decision Matrix: Which One Do You Need?
The difference between axial fans and centrifugal fans usually comes down to the "resistance" of your system.
| Feature | Axial Fans | Centrifugal Fans |
|---|---|---|
| Airflow vs. Pressure | Excels at high volume, low pressure. | Handles high static pressure and system resistance. |
| Efficiency | Peak efficiency in low-resistance systems. | Highly efficient when overcoming ductwork/filters. |
| Space & Installation | Compact; often fits "in-line" with ducting. | Larger footprint; offers flexible discharge angles. |
| Noise Characteristics | Generally higher frequency; louder at high speeds. | Generally lower frequency; easier to attenuate. |
| Durability | Simple design; best for clean air streams. | Rugged construction; handles "dirty" or hot air better. |
| Maintenance | Simpler maintenance due to direct-drive options. | May require more frequent bearing/belt checks. |
When to Choose an Axial Fan
If your primary goal is to move a high volume of air for general cooling or air exchange—and you aren't pushing that air through a complex duct system—an axial fan is the correct choice. Axial fan applications typically include general warehouse ventilation, condenser cooling, or roof exhausters.
When to Choose a Centrifugal Fan
When the system creates high resistance, you need the pressure capability of a centrifugal design. Centrifugal fan selection is preferred for industrial processing, drying, or pollution control where air must be forced through scrubbers or carbon filters.
Can You Use Both?
In many industrial facilities, it isn't an either/or decision. You might use axial fans for general building exhaust and centrifugal fans for local exhaust systems that require high-pressure filtration.
Making the Right Call
Choosing the right fan involves balancing CFM requirements with static pressure and spatial constraints. If you're looking at a spec sheet and aren't sure which direction to go, Hartzell's engineers can help you evaluate your specific application.
Get in touch: 1-800-336-3267 or info@hartzell.com
Frequently Asked Questions
Which fan type is more energy-efficient?
It depends on the operating point. Axial fans are more efficient for high-volume, low-pressure tasks. In high-resistance systems, a centrifugal fan will be more efficient.
Are axial fans louder than centrifugal fans?
Generally, yes. To achieve high airflow at low pressure, axial fans often run at higher tip speeds, which can create more high-frequency noise than a centrifugal blower.
Which requires more maintenance?
Centrifugal fans are often built for "dirtier" air and heavy-duty use but have more complex drive configurations. Axial fans have simpler designs but can be more sensitive to blade wear if the air stream contains abrasive debris.
How do I know which one I need for my ductwork?
If your system has multiple bends, filters, or long runs, the static pressure will likely be high, favoring a centrifugal setup.