Are you looking to measure draw for one specific device or across circuits in your whole home. I’ve been considering two systems: IoTaWatt and Lantern Power Monitor. Both are open source and open hardware.

IoTaWatt uses entirely custom hardware for the actual device but serves its own webpage that can be accessed easily at home from any device and if you’re technically savvy can pass to other services. My reservation with it is if at some point in the future the hardware dies, how easy will it be to recreate if the main project goes dormant, even with the hardware open source? What if a chip manufacturer goes out of business or discontinues a part?

In contrast, the Lantern Power Monitor runs on Raspberry Pi with a relatively basic custom board you can solder yourself with minimal skill; I suspect you could even make it work with a breadboard. Recent shortages notwithstanding, Raspberry Pi seems to keep their models pretty available for a long time, so that inspires a little more confidence. On the flip side, the software primarily runs on a mobile app. There is an iPhone app but it doesn’t have as many features as the Android app. But what happens if the project is abandoned and the app is no longer updated to stay compatible with newer phones or operating systems? And the app by default sends the data to an outside server maintained by the main developer. He doesn’t charge for the hosting and it makes it easy to access from anywhere, but some people might have concerns about that. You can also configure it to self-host from the Raspberry Pi but then you need to have the know-how to make it accessible outside your home (if you want). Underneath it also relies on some other open source data analysis components and I assume if you really know what you’re doing you can pass it out to other software.

Of course, in the end I don’t have the budget to do either project right now.