Can you fellows give me some recommendations on 12v 120mm or 140mm fans to be used at the end of a long run of 8 inch HVAC ducting? The ducting will be running from the top of an enclosed home theater equipment cabinet and I will install multiple fans at the end of the run to pull hot air out of the cabinet. The fans will be mounted in a custom box to which the ducting will be attached.

Of course quieter is better but noise level is probably not as important in this application as is CFM and fan lifespan. Given the application the fans will be used in, what fans would you recommend for the job?

Thanks,
Alan

What's your budget? These TY 140's from Thermalright are fantastic for the price, they surpass Noctua's and mount into 120mm brackets. $15
http://www.frozencpu.com/products/11677 ... Mount.html

You could also go with Gentle Typhoons or Noiseblockers, though you may be able to get away with louder/higher CFM fans because your duct will be far from the HTPC right?

Yes the end of the duct will be in a workshop a long way from the home theater cabinet. I don't have a limit on the fan budget.

I've read some good things about the Gentle Typhoons but didn't know if they would be good for this application. From what I understand, some fans should not have hot air blowing over them? Does that affect the bearing life?

how long is the run? how much heat do the components generate? whats your maximum ambient temperature at the cabinet intake?

I would skip pc fans and go more industrial,
http://www.4hydroponics.com/growroom/it ... ctBooster8

Yep, if it's far enough away and you just want air you can have a very high CFM industrial fan shoving air to your HTPC. Since noise won't matter...

I had considered using an industrial type fan like that but I would like it to be somewhat quiet. The fans will be about 15 feet from the cabinet. I don't know the thermal load yet but from what I can gather on the AVS forum I think 100 to 135 CFM should be adequate, maybe more than adequate.

In addition, I'd like to be able to control the fan speed and CFM. There will be intake vents feeding two 8 inch ducts in a false wall and I dont want so high a CFM that you will be able to hear the intake air rushing through the vents. I can somewhat control that by using a larger vent size but aesthetics will come into play there. Also thinking long term, PC fans will be easily replaceable when they wear out.

I've used speed controllers that I think came from coolerguys in the past with good results. So while I know there are a lot of quiet fans out there my main worry was about finding a fan that could pull through that ducting run. I'd also like to use dust filters on the intake side, as unrestrictive as possible. I'm thinking 3 or 4 of the Gentle Typhoon AP-15 fans per 8 inch duct might pull enough air through this setup. What do you think?

PC fans are not designed to pull through duct work. you will lose a lot of cfm with a PC fan and 15' of ducting, especially if the ducting is not smooth/straight.