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Shelly relays for energy monitoring
(forum.uncomfortable.business)
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Depending on how accurate you need your energy usage data to be for individual devices, you might be able to get away with just using a whole-house energy monitor. I'm using one of these:
https://www.amazon.com/gp/product/B08LV8DDFP
I already have a large number of Zigbee plugs, so by looking at the power usage from my energy meter before and after one switches, I can get a general estimate of how much power a device is using. Of course, the rest of your home is going to to skew the results, but you can mitigate this a bit with some of HA's statistics functions. It's been a while since I tried this, but I did test it with a 3.5kW heater a while ago. I took a median from a certain number of samples before and after the heater switched on (I think 10 seconds worth of samples), and the result was generally accurate to within about 100w.
Oh sorry; my goal here was for individual metering. I've got an Enphase solar system, so the Envoy is already doing whole-house monitoring.
I'd like to be able to identify and ultimately be able to lower my load to stay under what the solar panels are generating, but that needs data I mostly don't have, and specific equipment to actually turn things on and off.