Computer Fans, Push or Pull?

[stuckstuck]

Hi, I'm going to be buying a few fans for my computer case but was wondering which type of fans would be best?
From what I've read up online there's static pressure fans and there's air flow fans; SP fans are best for push whilst attached to heatsinks and radiators etc whilst air flow is best for pull in open spaces?
But the thing is I want 2 fans at the bottom of my case, the fans will be on the inside of the case however on the outside of the case where the bottom fans are installed there is a dust filter type tray there.
So there's the fine dust filter, then the bottom fans, and they'll be blowing air IN.
I would think that seeing as there's a fine filter there that the SP fans would be chosen, but seeing as the filter is behind the fans and not in front, that it would require a more powerful pull, meaning the AF fans??
Help.

 

[ignatzatsonic]

I would think that seeing as there's a fine filter there that the SP fans would be chosen, but seeing as the filter is behind the fans and not in front, that it would require a more powerful pull, meaning the AF fans??
Help.

I think you're generally right that static pressure fans are designed for use with heatsinks rather than as case fans.

But I'm not sure how much that distinction matters in the real world. A given static pressure fan like the Noctua NF-F12 might work well as a case fan in any given situation. Testing would tell.

If I understand you correctly, air passes through the filter before it reaches your fans. My first idea would be to just use a common case fan sucking air in through the filter. Even if the air passed through the fan before it reached the filter, I don't know that something as insubstantial as a filter would mean that an SP fan would necessarily be the best choice----filters are much less resistant to air flow than a stack of heat sink fins.

I wouldn't agonize over it. It's virtually impossible to accurately predict performance without actually testing anyway and differences may be so small as to be meaningless. Some degree of experimentation may be needed and you'll likely end up with some spare fans.

I would:

• Read reviews
• Concentrate on known good brands
• First try a minimum number of fans to simply guide airflow from front to rear
• Realize there's a point of diminishing returns where adding another fan has virtually no value
• Make sure your candidates have the proper connectors
• Consider PWM case fans if your motherboard has decent fan control and the appropriate headers
• Avoid anything smaller than 120 mm if possible
• Stay constantly aware of the major effect of the ambient temperature
• Get a case with known good airflow and cable management
• Avoid cases with a lot of mesh, unused case mounts, or vents if noise is a factor.
• Eliminate noisier fans from consideration although that's difficult without experimentation
• Expect any 120 mm fan that is spinning above 800 or 1000 rpm to be audible in most situations
• Be willing to say "Hello, I'm a fan-a-holic" if it applies to you

 

[stuckstuck]

Right, I figured that if there was a more preferred type of fan for this instance I would go for the more leant-towards choice.
In any case I'm probably going to go for the air flow pull fans, seeing as it's the filter then the fans inside.
Given that it was the other way around I would obviously go for the push fans, seeing as it needs to push through that filter in front of it.
I would just rather ask all the questions now so I would just know from there on out what's what.
Hello, my name is stuckstuck, and I'm a fan-a-holic.

 

[Layback Bear]

Let me see if I can make it easy.

Case fans are design to move volumes of air into a open space like a computer case. The restriction of a filter will have no measurable difference.

When moving air through a radiator of some kind I use hight pressure fans push/pull. Both push and the pull fans are high pressure fans, (matched).

Some radiators will allow more air flow with less pressure. It all depends on how the radiator is made.

My system has 14 fans. All case fans are just that, case fans and all my intake case fans and intake radiator fans have filters.

You can use high pressure fans for case fans but they will normally be louder and have less air flow volume. It is best to have a volume of air moving through a case. You need more intake volume than exhaust volume in a case. That will create a small pressure (positive pressure) in the case which will help in keep dust out of the case if all intake fans are filtered.

Filters on fans are not considered a restriction to worry about. Any fan will overcome the slight restriction of a filter with out a problem.

Of course I don't filter exhaust air; their is no need to.

If I was only going to use one set of fans on a radiator I would set it up as push. Most hight pressure fans push air better than they pull air through a radiator.

If you have anymore question just ask. Believe me I have tested many method of installing fans and measured the results.

 

[linnemeyerhere]

There are some new EK fans coming soon boys and girls and they are some seriously amazing fans from what I hear.......actually don't hear! This coming from the Noctua man.
Here's the link: http://www.ekwb.com/ Wait for it ...it's new and more of a tease !

 

[Layback Bear]

Thanks linnemeyerhere for the information.

EK is known for nothing but quality so I will be watching for test results.

 

[AddRAM]

Corsair Air Series Case Fans â

 

[essenbe]

I have 2 Noctua Industrial 3000RPM fans in pull only on a Corsair H105. They do great. I can turn them down to 1800 RPMs and feel the air coming through the radiator. At full speed, they are loud, but they put out more static pressure than any other fan I have found so far. They seem to do as well in pull as they do in Push. There is no such thing as a quiet 3000 RPM fan. But these are pretty good, and the air they push and the static pressure they use, means I can turn them down and get the same or better airflow and static pressure as I would from most any other fan. Plus, if I need to, I can turn them up and get 110 CFM of air and 7.63 mm H20 static pressure..

 

[linnemeyerhere]

Steve I'm looking forward to trying some of these new Noctua's one day but I keep snapping up the beige on sale and just have too many new ones and working ones in my rigs to justify the purchase yet but it's great to hear....or not hear how well there working for you !

 

[essenbe]

Well, they do the job. If you demand quiet, they are not for you. But they do the job and you don't have to run them full speed. I'm still playing with mine to see where I can run them without making a big difference. I have run them at 1900, 1800 and 1500 so far without much change.

 

[essenbe]

I have them on a Lamptron FC5 fan controller and just turned them down to 1300 and it doesn't seem to make much difference in temps. I'm running 25-30 right now, about the same as before. I don't think I can turn them down any more on this controller.

 

[AddRAM]

I love my Corsair HPE SP 120`s on my rad, they ramp up nice if the liquid gets warm.

Air Series SP120 PWM High Performance Edition High Static Pressure Fan Twin Pack

I`m gonna replace my blue led fans with this set.

Air Series AF120 LED Red Quiet Edition High Airflow 120mm Fan - Twin Pack