I know of sense.com but perhaps there are others?
For an easier approach, there are a bunch of wifi plugs that can report energy usage: https://www.androidcentral.com/which-smart-plugs-are-best-mo...
- amazon page (even if you buy from their website, they just order it to you off amazon): https://www.amazon.com/dp/B08CJGPHL9/
- install instructions: https://gist.github.com/flaviut/93a1212c7b165c7674693a45ad52...
- source code: https://github.com/flaviut/esphome/tree/emporia-vue
You can also get any of a variety of temperature sensors (I like SensorPush) and stick one in the fridge to get a pretty good idea of how much it's running the compressor.
Another thing to look at if there's central forced-air heating/cooling may be whether it's set to have the fan always running. That can be useful in balancing temperatures between floors, but it's still a fan using electricity to move air.
I've been out of the space for a while, but the "sense" power monitor was new when I left. It claims to use AI so you can just monitor the mains and it will suss out what is using power.
There were a lot of our home customers who were very obsessed with power use (trying to get to net 0 with solar). There have to be forums for this...
If you are looking for the manual way. getting a kill-o-watt and attaching it to your outlet is one way to see one of the things that takes a lot of power. I have the "Belkin" version which I like because the display isn't near the outlet. I'd suggest fridge... In my case my fridge was a large % of my power bill. Any electric heat.
When the monthly cost gets up to a certain level, we clean the coils and it drops back down.
I ordered the additional sensor that I'll use for the heat pump and one more circuit and see if it does any better, if not, the Emporia seems reasonably priced for as many sensors as it has.