Fans ~> CFM

[LiquidPenguin]

Usually I can find all sorts of information on the web. I can ask people and get answers. I can check posts and find them there. I would even patiently read badly written articles for useful tidebits. But there are two pieces of information that I can't find, and no one will answer.

The first is more important to me at this moment in time and the only one I ask here.

How does the average penguin such as myself determine the correct CFM for a fan? I've gone to stores that have scads of fans. After blowing a few bucks I came home with three or four fans. Two no-names and two, the store claims, are brand names. Point is two had no CFM rating and two did. However, their ability to push air around seemed to vary wildly from one to the next.

In the past, I've purchased fans that claim XX CFM but only seem to push 1/2 that. Remember the "card" fans that fit into an unused MB slot and pushed air through the back? Yeah, I got suckered into that.

Frankly , I'm sick of B.S. ratings and tired of reading articles about the same six fans. How does one measure the air flow through a fan and accurately (sp?) come up with a number that can be compared against other fans?

[It_The_Cow]

It's too hard to find by yourself. Too many variables come into play. Your main bet is just to trust the manufacturer and use your own logic to see if their claim is reasonable

[eobard]

A good thing to do is get manufacturer info and model numbers and then check their site. Even if you don't have serial numbers you could check the site based on physical characteristics of the fans and narrow down which fan you have, or could buy from a local supplier, to a handful. I just got a fistful of fans less than a week ago and when I got home I checked the manufacturer's site and found the ratings for them. Mind you it's better to do that before you buy but in my case travel time and costs didn't make that feasible. Also you could see if the store will hook one up and let you feel the flow, you wouldn't have numbers but you'd know if it was a strong or weak fan at least, that's what I did so I knew I wasn't buying a dud.

[CrackedSKull]

also in real life you'll never get that close to the max cfm a fan is rated. Air pressure, all kinds of resistance, especially inside a case, take a major blow on the actual cfm.

[_Will_]

just buy a 230.....even if it works "crapily" then it'll still be "good enough"...hehe


and if it turns out too powerful? thats good too! (unless for some reason your sensative ears can't take the noise...then u can just lower the voltage a bit...not too difficult)

[el]

do a google on the model number should find the info that way.

[LiquidPenguin]

:( Sigh, I figured as such. Just wanted to get an answer since I sometimes see articles that have graphs and what not between fans.

I recently picked up a few "largish" fans that have a "claimed" output. They push quite a bit of fricken' air but I wanted to see if the claim is accurate.Oh well.

[jbslow]

Do a search on "Air Velocity Indicators" or "Anemometers" , I was looking through a Granger catolog and I remmember seeing these things the measure air flow in FPM ,CFM ,CMM and they are not cheap the cheapest one I've seen was 255.00 dollars US. Well if you've already own a digital multimeter with 200V DC or more you can get a "Vane Anemometer Adapter" for around 100 bucks.