How Many Fans Should a PC Have? [Explained]

When it comes to gaming PCs, the biggest risk most builders are concerned over is the hardware heating up and dying. You need to allow air to safely enter and exit the PC case to keep your PC cool effectively. When building a gaming PC for the first time, you might be wondering how many fans should a PC have for optimum airflow.

While there’s no universal answer, as there are all kinds of PC cases, we’ll try our best to provide you with enough information to make an informed decision when buying cooling fans for your PC. 

How Many Case Fans Do You Need? 

A general rule of thumb for most standard builds is to use three cooling fans in your PC. Out of the three, two should be intake fans which should ideally be attached to the front of your PC case to pull in cool air, with the last one being an exhaust fan which should be attached to the back of the PC case to dissipate the hot air out of the build. This configuration creates the perfect airflow to keep your PC components cool and disperse a huge amount of hot air.

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But PC cases come in many different sizes and shapes, which means this configuration might not work for the PC case that you’ve bought. For example, a larger intake fan at the front and two smaller exhaust fans may function better for your case. Other PC cases also come with top to bottom fan configurations for GPU cooling too so that rule applies differently.  

The ideal airflow needs to have the best balance of both intake and exhaust air. If there are more intake fans in your PC case than necessary, there will be a buildup of hot air, and the exhaust fan won’t be able to push out that air in time which is also called positive airflow. On the other hand, if there are more exhaust fans, the cool air would exit the PC case before it has time to circulate inside the PC due to a lack of intake fans; that’s called negative airflow. So regardless of the PC case, to achieve the best airflow to keep your components cool, you need to maintain a proper balance of positive and negative airflows. 

How Do PC Fans Affect Temperatures?

Testing out different fan configurations on a PC will tell us a lot about how many case fans should a PC have. For this, we used the benchmarks provided by YT/Tech YES City. The case used for the benchmark was InWin 103 Case, along with Intel Core i9 9900KS CPU and ASROCK RX 590 for the GPU. The whole system comprises three bottom fans, two at the side and one at the back of the case.  

For CPU 

From the benchmark, we can see the Intel Core i9 9900KS was reaching the maximum of 88°C with none of the fans working. we can say there was a 7% improvement in temperatures after adding only one fan exhaust fan. We can also observe that when disabling the 3 bottom fans that interfere with the airflow of the CPU, there wasn’t a large change.

On a spectrum of the rest 3 configurations from one fan to six, we can see the maximum temperature was the same 83°C regardless if the side panel was on or off.  

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On the other hand, the average temperature can be seen reduced from the highest 79°C to 72.3°C, with the highest coming from all case fans being turned off and the lowest coming from the 6 x 120mm fan configuration. However, there were still not a lot of improvements, as can be seen in the benchmark. 

Now you could go and attach all fans in your build, but you should know that the difference is very minor when comparing one fan with six fans.    

For GPU 

Regarding GPU, we can see that by just adding one exhaust fan to the mix, there was a big drop in temperatures from 84°C of the no fans test to 78°C. After that, the results were pretty much the same for one, two, three, and four 120mm tests, with the temperature being at a consistent 78°C.

After adding another fan, we can see a drop to 77°C and another 76°C after adding the last fan. Lastly, there was a drop to 74°C that was observed after removing the tempered glass side panel.  

What this means is that there was almost no difference in temperatures between one fan vs six fans. However, it’s worth mentioning that by removing the tempered glass side panel, we can see a nice difference in temperatures.

This usually means the case isn’t set up for the best airflow, so it can be used as one way to check if you have the best airflow setup for your PC.  

The main takeaway from all this is that fans do have an effect on your PC’s temperatures, however small it may be. Now this difference could increase or decrease depending on your case. This is why it’s best to check the fan configuration that works best for your PC’s temperatures before spending too much money. 

How To Pick The Best Fans for Your Build?

There’re so many options to choose from when buying cooling fans for your PC case. While it may overwhelm you at first, there are some criteria to take into consideration that can make your decision easier. Depending on the type of environment you use your PC in, your budget, and lastly, your aesthetic requirements, you can pick from a multitude of different PC fans. It all depends on your personal preference. 

Environment 

To begin with, if the environment you’re using your PC it is humid, it could lead to high temperatures. So, to avoid this, you’d need powerful fans and good airflow. This directly affects your decision when buying fans as some might not operate well under very humid conditions.  

On a related note, fans also need to have clean, dust-free bearings to function properly, so if you’re in a dusty environment where your PC parts could gather rust fast, you might want to look into a specific dust-proof fan to keep your PC clean.  

Budget  

Like anything, PC fans come with variable prices with improved features as you go up the spectrum of your budget.  

Low-end fans will have lower RPMs and might be noisy compared to those on the higher end of the spectrum. Moreover, if the sound is a big problem to you when gaming, then this might directly affect your budget as low-tier fans don’t usually come with controllable RPMs, meaning they are always running at full speed and making all that noise. 

Contrastingly, higher-end fans are usually quieter and allow for stealth operation where the fans automatically adjust the RPM to function quietly and effectively. Higher-end fans will give you better RPMs and lower noise levels with RGBs to add to the aesthetic.

It’s not too much of a difference when it comes to performance alone, but features such as adjustable RPM, stealth operation, and anti-vibration pads can be quite useful.  

Overspending on fans is a big problem among newbie builders so it’s best to decide on whether you need those extra features and plan accordingly with your budget. 

Aesthetics  

Appearance and customization are a big part of building PCs. There’s no doubt that RGB fans alleviate your PC’s aesthetics to a new level. But there are some disadvantages to buying RGB lit fans, such as the higher price, extra wiring, and compatibility issues of the headers with the motherboard.  

Taking into consideration, the aesthetics could add or take away from your budget a lot as companies such as Corsair and 1st Player sell these parts for a higher price. With that said, it depends on you whether you prefer the looks to the point you want to spend more money on them.   

What To Look for When Buying Case Fans?

Now that you’ve figured out the best type of fans you need, it’s time to buy the ones that match your criteria. When it comes to case fans, there are so many options to choose from, and it can get a bit hectic.  

Case Type & Design  

Depending on the case that you bought, there could be anywhere from 2-10 spots where you can attach a fan. Even low-tier PC cases come with at least 2 available spaces to attach a fan.

With that said, you shouldn’t be so quick to fill all those spots with the case fans. In many cases, 3 fans could work just as well at cooling your PC compared to 6 fans.  

Take into consideration the type of case that you have and test out multiple fan configurations to see which one works best for you. If extra fans aren’t making any drastic changes to the temperature; it is advised not to buy them as they save money for other PC components.  

Diameter 

Another important thing to consider when buying case fans is its diameter since the longer the fins of the fan move, the more air they’ll produce. That said, case fans typically come in 3 different sizes.  

Firstly, the 120mm cooling fans are a popular choice because they offer fast RPMs due to the smaller fins they have to rotate. This also generates more sound unless you spend a few extra bucks for more quiet ones. In any case, they serve their purpose of providing good airflow for both intake and exhaust air.  

Next, the 140mm fans are the middle ground as they have a large surface area which provides more air to come in or go out, but they’re generally a little bit louder than the 120mm fans. They also have slower RPMs than 120mm fans but faster compared to 200mm fans.  

Lastly, the 200mm fans consume the most power and have lower RPMs, but they cover more area to provide the best airflow to your PC. They are most costly but serve as great intake fans. Consider pairing two of them as intake with a 140mm fan serving as outtake for a nice combination. 

RPM 

Generally, most cooling fans come with 900-1000 RPM, which are great for maintaining a balance of noise and performance. However, controllable RPMs are better as they automatically reduce the speed of the fans when the components aren’t running at high temperatures. This reduces the noise levels but costs more.  

Considering higher RPM gives you more airflow and performance, it also consumes more power and costs your fan’s lifespan. The higher the RPM of your fan, the more torque it produces to rotate its fins which puts stress on its motor.  

Ideally, you want a fan with the ability to adjust its RPM according to the components’ needs, as continuously running at high speeds can cause a shorter lifespan of the fan. Adjustable RPM fans are higher price but also worth investing in as they will much longer.   

Bearing 

The last thing you need to pick carefully is the bearing type. There are many types of bearings when it comes to PC fans made by different manufacturers. They’re important to take into account because they can give or take away from your fans’ lifespan. Fan bearings can be classified into the three most common types, which are ball bearing, fluid bearing, and maglev bearing.  

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Ball bearings are expensive and most popular because they’re durable and last considerably longer than other bearing types. They do produce more noise, but they are high-performance and very reliable.  

Fluid bearings are the cheapest option you’ll find when it comes to case fans, but they are also very prone to dust buildup, making their lifespan short. It would require a thorough cleaning if they stop functioning.  

Maglev bearing is becoming more and more popular as it’s more recent compared to other bearing types. It’s quiet and high performance and also quite expensive, but it will also last the longest.  

How to Install Case Fans on a PC?

Now that you know how many PC fans your PC should have, it’s time to test out the setup which you picked on your PC. 

The first step in mounting case fans to your PC is determining the airflow direction of the fans. Manufacturers usually put arrows on the rims of the case fans, indicating the direction of air. If you can’t see these arrows, you can turn on the fans for a bit and feel the airflow by putting your hand behind or in front of the fan.

Another way to do this is by seeing which way is the front or back of the fan because generally, the front part pulls in air from the front and pushes it out from the back.  

Now that you know the airflow direction of the fans, locates the fan slots available on your case. You can use a Philips head screwdriver to screw in the fans in these slots very easily. Don’t tighten the screws too much and screw them in diagonally for an even installation. Repeat this for all the fans that you bought. 

As mentioned before, the best place for intake fans is in the front. This position gives the fans enough cool air to pull into the PC case. Similarly, outtake fans or exhaust fans should be installed at the back to push out the air.    

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Conclusion 

When it comes to building PCs, the first thing to come to your mind is probably not going to be how many fans you need in a PC. But they’re still vital in providing good airflow in your system to increase the lifespan of your PC parts.  

In this article, we answered the question of how many fans a PC should have and gave you all the criteria which you should consider before buying case fans. For most cases, the 3-fan configuration of two intakes and one outtake fan works best. After that, it generally goes into the stage of diminishing returns as the difference in temperature isn’t really worth the cost