I just installed the Emporia Vue WiFi home electricity monitor. It was $100 on
Amazon and came with a main power meter along with 8 branch circuit monitors.
Installation was a breeze and I didn't get shocked while working on live circuits, for a change. The app was simple to use and is working very good.
The individual sensors won't register anything below about 35 watts, but once above that it seems to be fairly sensitive and precise. Small loads below 35 watt can be seen in the main consumption sensor as long as the total is above 35 watts.
There was 1 circuit that appeared to draw nothing, so I shut it off. Then I decided to turn it on, and I heard a hum coming from the panel, and perhaps elsewhere. The app showed the 120v 15a circuit spike to 7,000 watts (accidentally had multiplier set to 2 in the screenshot). About 4 seconds later, it flat-lines and never registers again. If I flip the power off for a couple seconds and back on, nothing. If I let it rest a minute, I'll get another spike when I flip it on. What could this device be? Do sprinkler valves use transformers, and could that be what the brief heavy load is? It's labeled spare on the panel. I hate how haphazardly electricians document their work with illegible Sharpie scribbles.
In total, there are 4 circuits I don't know what they do, so I shut them off.
There are 3 switches inside the house I haven't found a function to yet. I discovered a switch in the coat closet that controls a single outlet under the eve of the roof outside. Finding that was a miracle. I need 3 more of those.