Computer fans can be horrid junk doomed to premature failure while consuming lots of juice and making lots of noise, or be highly engineered for extreme reliability, and effective quiet efficient air movement.
The Noctua NF-f12 is one of the latter. It moves 53CFM for 0.05 amps, and its static pressure rating is about 2x that of other 120mm fans which have the same/similar or higher CFM rating and draw 2 to 3x more amperage.
The Noctua fans have 6 year warranties and I have one appraoching that age..
The NF-F12 is very quiet and 0.05 amp draw is one AH consumed every 20 hours. It also comes with inline resistor cable options to run it at even slower speeds and lesser ampdraw.
The NF-F12 also comes in industrial versions that are IP52 or even higher rated, and one of tham can spin at 3K rpm.
3K rpm is quite loud, but Noctua also sells a PWM speed controller NA-fc1 that is more or less plug and play, so one can dial in a volume and airflow and acceptable noise level, and on the hottest of days it can move 110CFM for 0.3 amps, making it an incredible performer. It can also be slowed down to very slow and silent via that PWM controller, and to impeller speeds and amp draw well below 0.03amps.
So don't assume all computer muffin fans are the same. This market for 120MM 12v DC computer fans in incredibly competitive, and the higher end products design and engineering is impressive.
Another favorite 120mm fan of mine is the dual ball bearing silverstone FM121. This fan comes with a built in speed controller and one can extend the wires and mount the speed control potentiometer well away from the fan. It is also rated for upto 110CFM but only half the static pressure of the Noctua 3k rpm NF-f12, and the SS FM121 also draws 25% more juice to move that much air.
I've had one in continuous operation for over 7 years now and it sees several hours at 14.7v every day, though I am not sure of the voltage drop on its wiring to my ceiling.
My personal preference is for powerful fans, on a speed controller, and when their amp draw is neglegible at reduced speeds, I have them run 24/7 and not bother with temperature controlled activation/deactivation.
