How to Read and Interpret a Fan Curve Effectively

fan performance curve


Efficient cooling systems are required in today’s fast-paced industries. They are essential for different tasks such as industrial machinery, telecommunication equipment and ensuring a longer lifespan and better performance of proper ventilation. That is why understanding fan curves matters. Fan curves are important tools to engineers and system designers for providing the best selection of fans to suit their specific applications. By learning how to read and interpret fan curves, you will be able to enhance your cooling setup hence leading to smooth running of your equipment.
You could be having a data center with high-performance case fans or designing an intricate factory ventilation network. In either scenario, having a good grasp on the subject of fan curves is fundamental. This article goes deeper into fan curves; explaining what they consist of as well as how we can understand them effectively. Moreover, this article explains how someone can use such knowledge when making decisions that are rational enough about it especially when choosing fans for your projects.

What is a fan curve?

It is a graph that describes the functioning of a fan under diverse circumstances. It shows the correlation between static pressure, airflow (in cubic feet per minute CFM), and power (brake horsepower BHP) for the fan. They are indispensable to engineers, designers and even fans who need to pick out an appropriate fan for their needs.

Why are fan performance curves important?

One reason why fan performance curves are important is because at first, they provide useful information for controlling fans. By understanding the performance characteristics of a fan, which can be used to find the right operating point for the fan in any given application. The operating point represents the location on a system curve where it intersects with a fan curve, indicating that this is where such an equipment’s air flow rate and static pressure should be placed to satisfy the demands of the systems.
The second use of fan curves is in evaluating how efficient the fans are. Different operating points indicated on this curve can be analyzed to ascertain how effective and inefficient this device will be when utilized at these different speeds.
Lastly, it is possible to compare different models of fans using their performance curves so as to know one suitable them all. When you have been able to evaluate various scenarios, including efficiency while also keeping in mind about airflow rates and static pressures that are necessary then you are able to pick out one among these many options with graphs publicized by manufacturers which reflects upon real differences between similar objects.
In summary, if your aim is to cool your gaming PC, data centre, or huge warehouse, then knowledge about reading and interpreting fan curves will lead you into making the right choices in applications like these.
Fans performance

Key Components of a Fan Curve

To fully understand a fan curve, it is necessary to comprehend what the key components are. Let us dig into them one by one.

Static Pressure

This means the force exerted by the fan to overcome any resistance in the system. It is usually measured in inches of water gauge (in. H2O) and shows how efficient the fan can be when it comes to pushing air into tight spaces like heat sinks or radiators; higher static pressure means better ability to overcome resistance.

Air Volume (CFM)

Air volume, also known as airflow, refers to the total quantity of air that a fan can move over a period, which is mostly expressed as cubic feet per minute (CFM). This shows how good a given fan is at moving large quantities of air, which is important for general cooling of the system. The more CFM there is then there’s more that can be moved by that particular fan.

Brake Horsepower (BHP)

The other aspect to note while selecting a fun is brake horsepower, which refers to power consumed by this latter in order for it generate the required flow rate and static pressure. This has an immediate effect on the efficiency of fans as well as overall energy use within systems, and hence should not forget we must take this into consideration when choosing these devices.

Interpreting the fan performance curves

Analyzing Static Pressure against Air Volume Curve

The static pressure against air volume curve is the most encountered on fan curves. It shows how a given fan changes its static pressure with respect to air flow. Normally, static pressures decline as flows increase. By looking at this graph, you can tell much about the behavior of your fan.
A steep curve suggests a higher suitability of such a fan for high-pressure applications, e.g, CPU cooling and radiators, while flat curves suggest that it is good for high-airflow applications like case ventilation.

The effect of fan speed on fan performance

Fan speed is critical in determining how well a fan works. As you increase the speed of rotation, both airflow and static pressure also rise simultaneously. However, performance doesn’t always follow this pattern relative to revolutions per minute (RPM) change. For most fans, there are several lines in their curve, each representing a different RPM value.
From these lines, knowing what will be suitable for your needs is so easy using the topmost line which represents the highest possible value for optimum performance based on your requirements as well as preferences, since more noise results from higher speeds other than being all about efficiency only

Practical Examples of Fan Curve Analysis

AC Axial Fans Performance curve

Example 1: Understanding the GN120B Metal Fan Curve

The fan curve for the AC axial fan model GN120B Metal will be analyzed, and its likely implications on fan performance will be identified. This graph shows two different sets of data, one for 50Hz and another for 60Hz operating frequencies; the x-axis is airflow (CFM) while the y-axis is static pressure (mmH2O).
It can be observed that static pressure diminishes as airflow increases. For example, at low air flows (approximately zero CFM), the static pressure peaks at about seven mmH2O for 50Hz and slightly less than this figure for 60Hz. At around 80-100 CFM, the static pressure drops to near zero for both frequencies.
Comparing these curves shows that the fan performs better at 60Hz. For instance, when a static pressure of four mmH2O is reached, the 60Hz fan gives approximately forty cubic feet per minute, while the other frequency gives slightly less. This presents a case where more speedy rotation improves airflow, hence effective cooling in various applications requiring it.
These curves help you choose an appropriate fan. If your setup requires higher static pressure with moderate airflow, then you should go for a 60-Hz operation. On the other hand, if you need constant air flow with reduced noise and energy consumption, then fifty Hz might be ideal. This means that through this analysis, we are sure that we have selected a cooler that works best within an efficient budget while meeting our general cooling needs.
DC Blower fan curve

Example 2: Interpreting the GR5015 DC Blower Fan Curve

In the graph, it can be seen that as the speed of the fan (RPM) increases, both the airflow and static pressure improve dramatically. An example is when at 6500 RPM, the fan produces a static pressure of up to 25 mmAq at low airflow (0 CFM), which declines gradually until it reaches an airflow of 3.5 CFM. On the other hand, in a case such as that of 4300 RPMs, with more air flow, it is surrounded by disarrayed small maximum static pressure values.
Fan curves demonstrate how adjustments in fan speed can control fan pressure and performance. For example, higher speeds (6500 RPM) give bigger amounts of static pressure and airflow suitable for applications requiring high velocity and a strong cooling system. Conversely, lower fan speeds (4300 RPM) are associated with reduced noise levels and power consumption, so they are considered best for silent or not intensive cooling purposes.
It’s therefore essential to understand this form of fan curve so that optimal performance can be achieved under different scenarios where fans are employed. Meanwhile, operating at higher RPMs is ideal for applications that require high pressures coupled with velocity. In cases where lesser fan pressures are needed while maintaining silence during operation, lower RPMs will serve best.

Applying Your Knowledge: Choosing the Right Fan

Armed with your newfound knowledge of fan curves, it’s time to put it into practice and choose the right fan for your application.
Choosing the right fans using fan curves

Matching Fan Curve Data with Application Requirements

Once you have an idea of what you need, then it is easy to start comparing fan curves. That way, you will find a suitable match. Prioritize certain parameters when choosing a fan. These include; the required air volume, system total losses and noise level. The fan you buy should be able to deliver the necessary air volume and overcome all pressure losses in the system.
Suppose that, for example, you were searching for a fan to cool your high-performance CPU. Here focus on fans having high static pressure, among other factors to consider. Alternatively, look out for pressurized vs airflow steep curve. However it is different if we are taking about case fans that are supposed to improve overall system aircrafts that’s totally another story in this case look for fans with high CFM ratings and flatter curves.
Meanwhile, there are also other things to be accounted for in renewable energy applications such as wind turbines, photovoltaic modules or battery packs used with them and so forth. In these cases, important factors include; high efficiency, low noise and corrosion resistance. This begins by going for fans which have higher efficiency thereby bringing down on energy consumption before selecting those which have met the requirements of noise within the premises where they will be utilized Finally ensure acquiring a corrosion resistant blower to avoid damages through rusting.
Application Priority Characteristics
High-performance CPU cooling High static pressure, steep pressure vs. airflow curve
Case fans for overall system airflow High CFM ratings, flatter curves
Renewable energy (wind turbines, photovoltaic modules, battery packs) High efficiency, low noise, corrosion resistance
Medical equipment (ventilators, extracorporeal circulation systems, operating room ventilation) High precision, low noise, high reliability

Practical Tips for Making Informed Decisions

Below are some practical suggestions that will help you make good choices while buying a fan:
  • Remember that testing methodologies may differ between brands, so always compare fan curves from the same manufacturer.
  • Noise level is also important, especially for those who want to have a quiet system. Fans with a good balance of performance and acoustics should be favored.
  • Also, don’t forget to consider the size of the fan and whether it is compatible with your system. Ensure that it will fit where you wish it to be placed and also has an appropriate connector type.
  • When making purchasing decisions, read reviews and look at benchmarks from reputable sources so as to know how well the fan fares under real-life conditions.


You now have the ability to read and interpret, like an expert, all those graphs which appear strange at first sight. The skill will also help you in selecting appropriate fans, among other things.
Match your fan’s performance characteristics with the requirements of your application for success. It enables you to choose the right fan by studying about its curve and taking into account factors such as static pressure, airflow rates, noise levels, etc.
Therefore, when faced with a challenge like this next time, don’t panic when looking at what seems like a complicated curve diagram. Take up this task willingly, using the knowledge gained in order to make wise decisions regarding cooling devices that satisfy your needs most effectively, instead of being intimidated by this diagram.

Quick Quotation

Wonderful! Share this Case:

Related Articles

Learn about fan bearings for cooling systems and their role in maintaining optimal performance.
Understand the differences between liquid cooling vs air cooling in industrial cooling systems.
Discover tips to address fan overheating problems and keep your system running smoothly.
Find the top DC axial fan manufacturer suppliers in the industry on our blog.

Contact Info

+86 183 1666 5997

+86 020-3667 8158

+86 020-8337 7440

Our Address

Building 4, No.7 Lanhua Street, Dagang Industrial Zone, Baiyunhu Street, Baiyun District, Guangzhou, China.

ACDCFAN is a professional manufacturer of high-quality AC axial fans, AC radial fans, DC axial fans, DC radial fans, and EC axial fans.

© Copyright 2023. Guangzhou Guanxie Fan Manufacturing Co.,Ltd. All Rights Reserved