The challenge on iMacs is working out what state it is really in.
There’s a screensaver timeout then, as you’d expect, an idle timeout, after which the screen goes off altogether. It still consumes quite a bit of power but after a further timeout the whole system should hibernate, consuming nearly no power.
Unfortunately there are many bugs and features that prevent hibernation from happening, and no status lights to tell you the difference between ‘screen off’ and actual hibernate. The only way to tell is to plug it in via a wattmeter, then wait a while before checking to see if it’s dropped to zero-ish. Mine generally needs a fair bit of quite difficult meddling, each OS update often undoing my efforts.
I’m generally a fan of Apple, and by no means a climate warrior. But I disapprove strongly that an awful lot of iMacs may waste an awful lot of energy in this way, the owners having no idea whatsoever there is any problem.
