Understanding Your PC: Positive vs. Negative Airflow

This discussion has a more recent version.
edited July 2022 in Computer Hardware

One of the most important factors affecting the performance of any computer is the airflow/air pressure. Anyone with a significant interest in maintaining their own PC should understand airflow and why it is important. Unfortunately, it's not as often talked about as something like How to Pick Your PC Parts, so both newcomers and veteran builders may not know all there is to know about airflow.

However, anyone can learn and implement proper airflow with a little bit of time and focus. This is why we’ve crafted this guide so that any newcomers to the world of proper PC maintenance will have a good foundation to build upon.

Why does Airflow/Pressure matter in PCs?

As far as performance goes, components such as RAM, processing power, and graphics cards are all very important. Personally, I am always looking for new ways to get more power out of my very own PC. This is why I know that there is so much more to consider and understand about improving PCs than simply loading one up with powerful parts.

The human brain is often compared to a computer. Factors such as memory, processing power, and performance output are all shared between them. A brain needs to filter out any intrusive thoughts that can clutter a person’s mentality and impede their ability to function in all areas effectively—a computer has a similar necessary function regarding airflow. If too many unnecessary particles make their way into its inner workings, it can greatly hinder the PC's performance.

Dust is one of the primary causes of computer-related problems and has nothing to do with technology at all. Dust can come from anywhere and travel into a computer at any time, no matter where a PC is or how it is set up. The worst part is that trying to block out any dust by enclosing the computer in a protective container will only increase the risk of overheating. In addition, dust can reduce the effectiveness of any computer component by its ability to corrode and degrade said component over a gradual period.

This is why I care and why anyone else should care about the airflow/pressure within their computer. The airflow of a computer needs to be regulated to ensure unhindered, efficient performance. Ignoring this issue for any possible reason could, unfortunately, lead to the untimely demise of an otherwise exceptional machine.

What is Positive Airflow?

PCs are generally built to encourage a vacuum effect, which causes a massive intake of the air from the areas immediately surrounding them. When the airflow reaches a point in which more air is going into the PC rather than leaving it, the overall air pressure is positive. Positive airflow is mainly beneficial towards clearing the particles that can sneak into a computer. When air is pulled in, the dust inside is forced to move out, which prevents it from building up and negatively affecting the PC.

However, if all the fans focus on positive airflow, then a huge problem can occur. If all of the air stays inside, the temperature actually stagnates rather than cools down. The heat of all the electrical components will then increase until the computer overheats.

What is Negative Airflow?

The air brought into the PC needs to leave as soon as it has served its purpose. Typically, any air entering the PC comes out almost instantly to maintain the desired overall air pressure. When the computer reaches a point in which more air is leaving than entering, negative air pressure has been achieved. Negative airflow keeps the PC at a cool and functional temperature. As a result, all of the heated air that can build up while using a computer is pushed out to prevent overheating.

Cases are usually not sealed in a way that prevents dust from entering through cracks and crevices. This is because the vacuum effect of positive air pressure does not apply to negative air pressure in regard to dust. Therefore, if there is no positive airflow, these undesired particles will sneak inside and accumulate without being forced out.

Which is Right for my Case?

The right fan for any computer case depends on a variety of factors. When building a PC, you’re effectively trying to address the correlation between the desired airflow, cooling parts, and the actual size of the case.

If I desire to use a smaller case and want a balanced airflow, getting a near equal amount of small positive and negative air pressure components would be in my best interests. A double fan or triple fan may be too large and take up too much space, resulting in unbalanced air pressure for my computer.

There is much more flexibility with a larger case due to the increased number of places for parts. You can place larger fans with the possibility of balanced airflow and less worry about unwanted imbalances. The utilization of one’s ability to consider the connection between size, parts, and airflow is all it takes to seek out a proper computer case.

Key Considerations: Warnings and Reminders

Hopefully, we’ve made it fairly easy to understand all the basic aspects of positive and negative airflow and its relation to the functionality of a computer. However, I often have found that even with a wealth of knowledge, the occasional mistake can occur unexpectedly.

Reviewing the basic principles is a great way to refresh one’s knowledge of computer airflow and any supplemental topics as well.

●    Never place the PC in a position in which it can overheat. This is ultimately one of the basic principles of computer maintenance. When a computer overheats, every single part within it comes at the risk of burning out, experiencing an electrical short, or even melting in some cases. An overwhelming focus on positive airflow can be the main culprit behind overheating.

●    Be aware of the possible over-accumulation of dust. As expressed previously, dust can be absolutely lethal to a computer’s performance. Therefore, you should regulate negative airflow to help prevent this from happening.

●    Size is an important factor in choosing cooling fans. Therefore, you need to choose fans carefully to achieve the desired air pressure while considering a case’s size limits.

●    Computers need both negative and positive airflow to function properly; how much is needed depends on the person’s needs. However, ignoring one form of air pressure entirely can cause irreparable damage to a computer.

Have All Your PC Needs Covered

Anyone who believes that they truly understand the complexities of CPU-related air pressure is ready to put that knowledge into action. Ready to get started optimizing your own PC? You can gain access to a wonderful collection of case fans and CPU coolers as well as our extensive CPU/GPU fan collection to find the right parts for your PC.

Of course, there are likely to be some people who still need a little assistance. For any other questions and specific details, any help or support will be provided by checking out our laptop and computer repair services.

More from the Micro Center Community:

Looking for more information about Building a PC? We’ve got PC Build Guides as well as articles on How to Choose Parts for your Custom PC BuildProduct Reviews, Part Comparisons, and even a How To Upgrade your Desktop PC guide! And if you can’t find what you’re looking for, don’t hesitate to post a new discussion and the Community will be happy to help!


We love seeing what our customers build

Submit photos and a description of your PC to our build showcase

Submit Now
Looking for a little inspiration?

See other custom PC builds and get some ideas for what can be done

View Build Showcase


If You Can Dream it, We Can Build it.

Services starting at $149.99