Just wanted to thank you for this nifty little applet.
My iMac's hard drive died, and when they installed a new one I upgraded to El Capitan, and I thought the continuous roaring of my hard drive fan was a software bug in the O/S (because they had such a problem in the Beta.)
It turns out that the shop didn't do whatever they needed to do to sync the O/S with the new, non-Apple hardware (I'm still trying to figure that out...,) but NO PROBLEM, because Macs Fan Control came to my rescue.