[aksss]

Surprised there’s not more mention of Shelly monitors in these comments. They’re great for whole house (service entrance) and circuit power monitoring. Pretty open integration, OOTB integration with HA.

I think it makes more sense to use “dumb” OTS circuit breakers in your house and augment with add-on monitor than combining the capabilities into a tightly-coupled single device.

[AdrianB1]

I use a dozen of their relays and I am happy with it; for power metering they don't have a great solution, the 3 phase clamp is very expensive and there is no option for more, like Emporia Vue with 8 or 16 sensors. So yes, Shelly is worth mentioning, but not for fine grained power metering.

[aksss]

The deployment model is very different, and within that model, the capabilities are far different. Comparing Shelly's system to Vue really starts with understanding your requirements and long-term automation plans.

I think the key differences are in cloud requirements, control, and granularity. Price appears higher than Vue, though it's not when considering that Shelly is far more capable in all of the above categories.

The Shelly 3EM, which I use for split phase monitoring (in the US) at the meter is $109. That's not bad for its capacity, capability, and build quality. Mine is outdoors though enclosed (necessarily) so endures some pretty extreme temp swings and humidity changes. There is no cloud requirement, and it offers contactor control.

The Vue 2 from Emporia is built for a single indoor panel, provides no control over the circuits, and requires the cloud to operate unless you get out the soldering iron and reflash it with ESPHome, which isn't horrible, but the OOTB cloud requirement is your starting point. (I think that's still the case, but if I'm wrong, happy to be corrected)

For Shelly, their additional clamp solutions are all high-amp (50-100+) so not really designed to be put on individual circuits, especially at $50 per. You might use these on whole panels, breaking your whole house calculation down into zones by panel or monitoring high-amp devices.

If you tried to replicate the Vue with only these devices from Shelly, then yes, it would be an order of magnitude more expensive. But I don't think that's a good way to use them or the right way to replicate the Vue capabilities.

For the high-grained monitoring, it's hand-in-hand with control. Shelly's deployment model for fine-grained resolution is to put power metering down closer to the consuming devices, and with it, a relay for integration into home automation. You can add power metering along with control to outlets, switches, or hard-wired devices in house with things like the 1PM Mini G3 for $13 per.

In this sense, you get far greater granularity than something like the Emporia Vue which can get no higher resolution than a whole circuit. Here again it must be stressed that with Shelly, there's no cloud requirement for that price and you're also getting remote control of the power distribution. On the balance, you're getting far more for your money with this approach.

For my needs, I combine Shelly's approach with some cheaper sonoff/tasmota plugs with power metering for things like the washing machine (alarming mostly). But for more critical devices or always on devices (like freezers), or switched devices like ventilation fans or lights, I think the build quality and deployment model of the Shelly devices is a better fit.

But definitely different target audiences. If the Vue is the right fit, it's the right fit.