Shelly Plus 1 vs Shelly Plus 1PM

The Shelly Plus 1PM wins clearly. It adds energy monitoring and a complete overheating, overvoltage, overcurrent and overpower protection set to an otherwise identical module, and it is the cheaper of the two. The Shelly Plus 1 offers no advantage beyond availability.

The PM, which stands for power metering. The Shelly Plus 1PM measures instantaneous power, voltage, current and accumulated consumption on the circuit it switches. The Shelly Plus 1 has no metering hardware, and also lists only overheating protection rather than the full protection set.

Yes. Both are 37 x 42 x 16 mm and weigh about 26 to 27g, both switch up to 16A on AC and 10A on 30V DC, both offer dry and wet contact modes, both need a neutral wire and both restore their state after a power cut.

No. Neither the Shelly Plus 1 nor the Shelly Plus 1PM supports Matter, Apple HomeKit, Zigbee, Z-Wave or Thread. Both work with Alexa, Google Home, SmartThings and Home Assistant over 2.4GHz Wi-Fi, and both can run entirely locally with no cloud account.

Buy the Shelly Plus 1PM for almost any single-channel job: it switches 16A AC or 10A DC, isolates with dry contacts when needed, tells you what the load consumes, and protects against overheating, overvoltage, overcurrent and overpower, with a 3-year warranty.

Buy the Shelly Plus 1 only if you find it cheaper than the 1PM and have no interest in consumption data. It is the same UL-listed hardware minus metering, with dry contact isolation, AC and DC support and a 3-year warranty, and it still requires a neutral wire.