2026 verdict
On a single appliance circuit such as a water heater or a boiler, the
Shelly 1PM Gen4 is the better metered smart relay of these two.
It adds native Apple HomeKit and Matter support, a Zigbee radio that doubles as a mesh router and a dry contact mode, and it is rated for 16A resistive loads against 10A per channel on the older module. The
Shelly Plus 2PM keeps one clear advantage: two channels, which also unlock its interlock mode for roller shutters, blinds and curtains. Both meter energy, both carry the full overheating, overvoltage, overcurrent and overpower protection, both need a neutral wire and both come with a 3-year warranty in the same 37 x 42 x 16 mm body. Pick the
Shelly 1PM Gen4 for one heavy or metered load and for Apple Home or Zigbee homes, and the
Shelly Plus 2PM when two circuits or a motorised cover share one switch position.
What owners say
Owners of both Shelly relays agree on the basics: energy readings they actually use and local control through Home Assistant that responds instantly. Where they split is the job. Shelly 1PM Gen4 owners describe watching a water heater, furnace, dehumidifier or electric boiler and building automations around real consumption, and they like picking Wi-Fi, Zigbee or Matter to suit the setup; their complaints are a wiring diagram they had to decode and a Zigbee mode switch that takes firm button presses. Shelly Plus 2PM owners talk mostly about shutters and curtains driven from an existing switch and about years of reliable use across many units, and they mention the module running warm and the lack of position feedback on a cover.
