Here is my views on fan controllers.
The vast majority of them use undervolting to slow down your fans. By undervolting I mean that the controller will just waste away the voltage to control your fan.
For example, pretty much all PC fans run on12v. So if you have a 2000 rpm fan you want to slow down to 25% speed (500 rpm) the controller will reduce the voltage from 12v down to 3v (25% of 12v). But to do so, the controller will simply burn away 9v of electricity and turn that 9v into heat. So most fan controllers produce a lot of heat, some can even be fitted with water blocks to cool them down. Such is the case of the Aquaero. But water or air, they all require heatsinks to be kept cool. That heat, where do you think it's going?
-Yup, you got it, that fan controller is helping to keep your case nice and toasty!!
And here is the kicker: the more you slow down your fans, the harder your controller works, and the more heat it produces because it has to burn away more voltage.
Also be aware of claimed wattage per channel on these undervolting controllers. Some guys will plug a bunch of fans on a channel, crank it up to full speed and say "Yup, that channel lives up to it's claims". But if that guy tried to turn down the speed of these fans, the controller would smoke up and burn.
There is only one brand on the market that does not use undervolting to control your fans. It's the Lamptron brand.
Instead, Lamptron uses power modulation which produces no heat and wastes no voltage.
I bought the Lamptron Touch because I like that it has clean sober lines and a touch screen. Thought, that touch screen could be improves it's still a great controller. Will control 34+ fans with it while producing virtually no heat. Name me an other controller out there that can do that?
Also, because it's power modulation, I can slow down my AP-45 fans from 2150 rpm down to about 200 rpm. That's less than 10% speed. Name me an other that can do that?
Edited by PepeLapiu - 1/27/13 at 10:27am