Nothing can do this accurately. Anything that has a single probe on the circuit that gives a "per device" or "per circuit" readout is simply guessing.
To expand on this a bit with my approach. Anything that plugs into an outlet has a smart plug. This gives me individual power reading for rules, as well as granular energy costs using my app: [RELEASE] Energy Cost Calculator [BETA]
I recently installed IoTaWatt with leads on the mains and the breakers for my two outdoor compressor units for the AC. I wrote a new device driver to pull energy and power readings from it: [RELEASE] IoTaWatt+ [BETA]
I now have the option to track total energy usage for the house as well as setting up rules to alert when something is on/off. Washer, dryer, oven (gas, so not much I can do to check for a burner using this method), etc.. my plan is to aggregate some of the power meters into a rule for power outage notifications so I'll know whether the whole house is out versus individual circuit.
