Whether it’s for improving cooling or replacing broken fans, knowing how to install fans in a PC is an essential aspect of owning a PC. It’s likely not something you’ll be doing regularly, but it’s knowledge that’ll come in handy as you upgrade and build new PCs over the coming years. Let’s get to it.
How to Install Case Fans
This guide presumes that you’ve already figured out how many fans you need and how to best set up your fans for optimal airflow. If not, check out both guides first to help you decide on placement and quantity.
You should also check out our guide to measuring case fans if you need help finding out what size fan you should buy. We recommend going with the largest fans your case supports for the best balance between noise and cooling performance, but that’s up to you.
Step 1: Identifying Case Fan Airflow Direction
Before installing fans, you need to identify which way your fans blow. You almost always want front-to-back airflow, with fans sucking in cool air at the front and blowing it out at the rear. So knowing which directions your fans blow is essential to set this up correctly.
Identifying airflow direction can be quite challenging if it’s your first time installing PC fans. However, it’s actually quite simple. There are two ways to identify a fan’s airflow direction. The simplest method is to look at the grille as case fans blow in the direction of the protective grille.
Another quick way of determining case fan direction is to look for arrows on the frame. These arrows indicate the direction of both the blades and the airflow. Not every manufacturer includes these, but they look like this when they’re present:
Source: Voltcave
So, if you’re installing intake fans, you want both the grille and arrow pointing into your case, with the open side facing the case’s exterior. The opposite applies to exhaust fans, of course.
If you want to double-check your fan direction once you’ve installed and connected them, simply power your PC on and hold up a piece of tissue to the fans. The intake side will pull the tissue closer to the fan, while the exhaust side will blow it away.
Step 2: Mounting the Fans
Now that you’ve figured out the direction the fans need to go in, it’s time to install your fans. We’re not going to go through where you should or shouldn’t install fans; the guides we’ve linked previously will help you figure that out.
Mounting cooling fans is simple: hold the fan up to the correct mounting holes and screw the fans in with a Philips head screwdriver. Almost all fans will come with screws in the package; you can use those or reuse old screws if you’re replacing or upgrading fans. Once you’ve installed the fan, it should look like this:
Source: Voltcave
Depending on your case (and mounting position), you may need to remove parts of the case like the front or top panel to install your fans. Refer to your case’s manual for this, as each case is different. Follow the case manufacturer’s instructions here to avoid damaging your case.
When installing fans, rotate them so that the fan cables come out from the fan in a convenient position for cable management. Generally, you want the cables to come out on the motherboard tray’s side. This makes it easier to hide them and minimizes the distance to your motherboard’s fan headers.
Step 3: Connecting the Fans
Once the fans are screwed in, it’s time to connect them to your motherboard or a fan controller. We prefer connecting fans to the motherboard whenever possible, as it gives you control over each fan when using fan control software.
Simply look for the closest motherboard fan header to the fan you’re trying to connect. Depending on your motherboard manufacturer, they’re usually labeled either SYS_FAN or CHA_FAN. The positions will differ depending on your motherboard, but you’ll usually find at least a couple on the front edge of your motherboard and some at the bottom, like so:
Case fan header locations on a Gigabyte B550 Aorus Pro AC. Source: Gigabyte
Some motherboards will allow connecting case fans to water pump headers, especially if it’s labeled SYS_FAN_PUMP like on the Gigabyte motherboard above. However, avoid connecting case fans to the CPU_FAN or CPU_OPT headers; those are for your CPU cooler fans and are better reserved for that purpose.
Once you’ve found a suitable fan header, it’s simply a case of plugging the fan cable into the header. These headers are keyed, and the connector will only go in one way. So there’s no chance of plugging your fans in wrongly.
Source: Corsair
While connecting fans to a motherboard is the gold standard, you may find that your motherboard doesn’t have enough fan headers for all your fans. This is particularly common with Micro-ATX and Mini-ITX motherboards, as they don’t tend to have many fan headers.
In that situation, you’ll want to use a fan hub. Many higher-end cases have built-in fan hubs, but you can purchase a decent fan hub like this Arctic fan hub for less than $10. You can also use fan splitter cables if you’re on a tight budget, although we believe fan hubs are worth the extra cost.
The main downside with a fan hub (or splitter) setup is that you won’t be able to control the fans individually. Instead, all the fans connected to the hub will use the same fan curve. Only plug fans you want to run at the same speed into a fan hub.
Fan Connectors and You
Modern case fans will have either three- or four-pin connectors. Three-pin fans are voltage-controlled, while four-pin fans use PWM (pulse width modulation) to control fan speed. Both are perfectly usable, but PWM has the benefit of letting you slow fans down to 500 RPM or so without them stopping, a boon for silence-focused builds.
Whichever fan you choose, you may find yourself plugging a three-pin fan into a four-pin header (or vice versa) on your motherboard or fan hub. While this might seem worrying, it’s not a problem: three- and four-pin fan headers are interchangeable, so there’s no risk of damaging your fans.
The only issue is that four-pin PWM fans need four-pin headers for PWM control; connecting them to three-pin fans means you’ll be using voltage to control your fans. So if you want to use PWM to manage your PWM case fans (and you should), you want to plug them into four-pin headers.
If your fan cables aren’t long enough to reach the headers or a fan hub, you can use an extension cable to compensate for the missing cable length. You’ll have one in the box if you’re installing a Noctua fan. If not, you can get a decent five-pack set for less than $10 from an online retailer.
Finally, you can connect your case fans directly to your power supply via a MOLEX connection if all else fails. MOLEX used to be the standard way to connect and power fans a long time ago, but it comes with the downside of always running fans at 100%. So it’s not ideal if you want to set up fan curves or like a silent PC.
You can get adapters to connect modern fans to your PSU’s MOLEX connectors. We don’t recommend this, but it is possible if neither of the previous options works for you.
Step 4: Testing and Final Tweaks
Once you’ve installed and connected your fans, it’s time to power your PC on and check that everything’s running correctly. Use the tissue tip we pointed out earlier to ensure that all your fans are pointing in the right direction.
While you’re at it, you should ensure that there aren’t any cables hitting the fan blades. This is to avoid any potential damage to the wires and avoid the annoying buzzing or ticking sound that happens when the two come in contact.
Once you’ve confirmed that each fan is pointing in the right direction and that there aren’t any cables hitting them, it’s time to set up your fan curves. It’s a somewhat involved process, so we won’t discuss it here. Instead, check out our guide to fan curves for a step-by-step guide to creating fan curves that balance silence with cooling performance.
Closing Thoughts
So there you have it: how to install fans in your PC in four simple steps. PC fan installation may seem slightly intimidating if you’ve never worked on a PC, but there’s really nothing to it. Just make sure your fans are pointing in the right direction, and you should be good.
Need some help choosing new fans for your PC? Check out our roundup of the best case fans for some great recommendations.
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