I just bought one of these - Belkin Energy Use Monitor to see what kind of power was being used around the house. A few minor surprises, none too bad.
So, naturally I have to try it on EVERYTHING. Which, of course, means my computer.
And if you check your computer power consumption, naturally, you have to check it while it's doing something power intensive. Like "flying".
All totals rounded off.
Well, what does it costs to "fly" with a fast i7 computer, 32GB of DDR5 RAM, three drives, an AMD RX 480 video card, 3 large monitors, and all the other little stuff?
Just the computer, doing nothing, and with just one monitor costs about $6, per month.
Each additional 23" monitor eats up almost $4 more, per month.
My computer, doing nothing, and with 3 monitors runs about $14-$15.
The same with Prepar3d running on ONLY the center monitor is about $16-17.
The same setup running Prepar3d in full screen mode across ALL THREE monitors, and with an outside view, hits the $26-$27 mark.
Making those numbers make sense.
Those numbers are real, but the power use is computed out to what the cost would be if the equipment were running non-stop for a full 30 days. The device will also extrapolate the cost, if run at that same power demand, for a full year.
This power monitor, and I assume others of it's kind, has a feature that will measure usage over a long time frame to give you a more accurate average, rather that just a steadily changing low to high usage.
Do you "need" one of these things? Not really.