Loud Fans, Power Reduction, and Other Reasons to Add Fan Control to a PC


Loud fans - Lamptron FC-Touch

The Lamptron FC-Touch, just one of many commercially available multi-channel fan controllers which can eliminate loud fans and help reduce power consumption.

The hardcore gamer or computer hardware enthusiast likely does not need to be convinced that having some method of fan control is a good idea. The user who has already spent hundreds of dollars or even more on a high-end PC, a graphics card with a powerful GPU, and possibly several other pricey peripherals will likely see adding a fan controller as a wise investment, especially since high-performance systems often incorporate loud fans. The average desktop user may not think having a fan controller is necessary, and they may be correct. For them, running the fan at maximum speed whenever the computer is on will provide a reliable method of cooling the system. Moreover, some fans have a lifespan of 60,000 hours, or almost 7 years of continuous use, thereby virtually guaranteeing that the fan will be one of the last computer components to fail, and seemingly giving the typical PC owner little justification for adding fan control.

Nonetheless, there are several advantages to  adding fan control to a PC. Although each user might have different reasons for wanting to control the fans, the following come to mind as the most likely justifications:

[1] Loud fans.

Modern PCs are a vast improvement over earlier ones in terms of noise output.  Anyone who had an XT or any of the other early PCs can likely attest to this; while loud fans are sometimes an issue, the fans generally are not as noisy as they once were. Still, as a fan runs faster, the noise generated by that fan increases exponentially. Since fan noise increases with the fifth power of the fan speed, reducing rotations per minute (RPM) by even a small amount potentially means a reduction in fan noise. Additional fans on a PC can increase the decibel level of the computer to as much as 70 dB. And loud fans are no fun.

[2]  Power consumption reduction.

While eliminating loud fans is enough of an incentive for many users to invest in a fan controller, the efficiency argument should be considered as well. Circuits consume electrical power; chips and transistors need power to operate, while components such as resistors will dissipate heat, which means more energy loss. Modern controllers can be made with low power consumption chips. For example, if we have a PWM controller operating at 5 volts (V) and drawing 30 milliamps (mA), we can calculate the amount of power consumed:

P = V*I = 5 V * 0.030 A = 0.150 Watts (or 150 mW)

In this example, we are using Joule’s First Law (power in watts = voltage in volts * current in amps, or P = V*I) to calculate the power.  That is 150 mW (milliwatt)  for the fan controller. A 300mA typical fan operating at 120 volts consumes this much:

P = V*I = 120 V * 0.300 A = 36 Watts

A fan controller would enable the user to control the voltage sent to the fan.  Assuming that the user runs the fan with half the voltage, the power consumption of the fan will be reduced in proportion to the voltage reduction:

P = V*I = 60 V * 0.300 A = 18 Watts (or 1800 mW)

The system will consume 150 mW of power that would not have been used if the system did not have a fan controller at all, but the fan is now consuming 1800 mW less than it was before. Thus, the net savings in power consumption is 1650 mW. Moreover, since most fan controllers can control multiple fans, the user can save even more power by reducing the voltage to several fans, while the power consumed by the controller remains the same, meaning that the more fans the system uses, the greater the potential power savings.

[3] Improved fan reliability.

All PC fans have bearings, and these bearings generate friction, which in turn will slowly wear the bearings, which in turn will lead to the end of the fan’s life span. By rotating the fan slower, the friction and the heat generated by the fan will be reduced, increasing the lifetime and overall reliability of the fan. This alone might recoup the cost of buying a PC fan controller.

[4] Dust accumulation reduction.

The air carries dust. Filters reduce the dust, but even with these filters, dust will get into your PC. This causes two problems: [a] it clogs up the filter and reduces the amount of air that goes ito the box; [b] dust sticks to the surfaces of chips and heat sinks, reducing their ability to disappate heat effectively and increasing the temperature inside the box. If the incoming air volume is reduced to the required volume for reducing the speed of the fan, less dust will be pushed through the filters into the PC.

[5] Aesthetics.

While the first four items on my list are the ones usually cited as the most common reasons for utilizing some form of fan control, it should also be noted that many of the newer fan controllers have been designed as much with an eye towards having an aesthetically-pleasing look as they are to work efficiently (the Lamptron FC-Touch pictured above is just one such example). Many of them have a means of changing the color of the LED outputs, and almost all of them except perhaps the most primitive ones have something to offer visually. Any user who is looking for an add-on that enhances the looks of the system (while potentially offering substantial benefits in the form of power and minimizing noise from loud fans) should consider adding a fan controller.


While there are many reasons one might want to install a fan controller, the most compelling reasons, in my opinion, is the potential for savings in power consumption and to eliminate the issue of loud fans.  If loud fans are the main reason you are considering installing a fan controller, you probably want to explore other options first.  If you are running an old system, clean all the fans and see if this resolves the issue. If you can isolate the noise to a single loud fan, consider replacing the fan. But keep in mind that even a perfectly good fan will get louder as it runs faster. If other options have been exhausted and you still have an issue with loud fans, it is probably time to consider a fan controller.

External Links:

Wikipedia entry on fan control


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