Shelly 1 Gen3 vs Shelly 1PM Gen4

The Shelly 1PM Gen4 is better overall. It adds built-in energy monitoring, Zigbee connectivity and a Zigbee router role on top of the shared Wi-Fi, Bluetooth and Matter feature set, and it carries the higher owner rating. The Shelly 1 Gen3 remains the pick for no-neutral installs or when you simply want the cheaper relay.

Energy monitoring and wiring. The 1PM Gen4 measures instant power, voltage and total consumption, while the Gen3 has no metering at all. The 1PM Gen4 also adds Zigbee but requires a neutral wire, whereas the Gen3 runs without a neutral.

Only the Shelly 1PM Gen4. It includes precise power metering for tracking an appliance's consumption. The Shelly 1 Gen3 has no energy monitoring, so if you want consumption data the 1PM is the one to choose.

Only the Shelly 1 Gen3. It is designed for boxes that lack a neutral, a common issue in older wiring. The Shelly 1PM Gen4 requires a neutral wire, so confirm your box before picking the metering model.

Buy the Shelly 1 Gen3 if your box has no neutral wire, or if you want the more affordable single-channel relay and do not need energy monitoring or Zigbee. It still delivers Wi-Fi, Matter, dry contacts and hub-free local control.

Buy the Shelly 1PM Gen4 if you want to both control and measure a circuit, or want the flexibility of Wi-Fi, Bluetooth, Zigbee and Matter with a Zigbee router role, and your box has a neutral wire.