I'm in the process of getting my Home Assistant environment up and running, and decided to run a test: it turns out that my gaming PC (custom 5800X3D/7900XTX build) uses more power just sitting idle, than both of my storage freezers combined.
Background: In addition to some other things, I bought two "Eightree" brand Zigbee-compatible plugs to see how they fare. One is monitoring the power usage of both freezers on a power strip (don't worry, it's a heavy duty strip meant for this), and the other is measuring the usage of my entire desktop setup (including monitors and the HA server itself, a Lenovo M710q).
After monitoring these for a couple days, I decided that I will shut off my PC unless I'm actively using it. It's not a server, but it does have WOL capability, so if I absolutely need to get into it remotely, it won't be an issue.
Pretty fascinating stuff, and now my wife is completely on board as well; she wants to put a plug on her iMac to see what it draws, as she uses it to hold her cross-stitch files and other things.
7 months later update:
I've expanded HA quite a bit and have a decent grasp on where my electricity is being used. Suspending my desktop has saved a shitload of power: under Linux, when suspended, it draws ~10W of power at any given time vs ~100W when idle. Also, I put smart plugs on the server cluster; the total usage of the entire cluster - 4 mini PCs, 1 SFF, and 5x HDDs (NAS) - over the last 7 months so far is currently at a whopping 465 kWh. That's ~66 kWh a month. Barely 5% of my monthly electrical usage.
If you want to expand from just monitoring a couple sockets to monitoring the whole house; I'd recommend Iotawatt. I've been using one of these to monitor every circuit in my house for a few years now.
You can use the built in webpages shown below to view it's internal graphs, or setup an exporter to feed the data into external DBs like influxDB+Graphana or Emoncms.
Very cool! However, my house is a rental, so any monitoring equipment has to be somewhat non-invasive.
Edit: it helps if I actually look at the product before spouting nonsense... Looks promising.
I'm in a rental too. It's non-invasive; just gotta pop the panel cover off, clip the transformers over the wires without disconnecting them, and put the cover back. It can all be removed just as easily.
Uh oh. Red flag.
This may be where the rental agreement is broken. Define 'pop' . Two hands and a tool? Clear it with the landlord first. The company running the 400-unit building where I am now is gonna say F No.
That's between you and your landlord. Mine was fine with it as it doesn't actually modify any of the wiring.
Spaces before a full stop? Really?