# Shelly 3EM Smart 3-Phase Energy Meter vs IotaWatt Open WiFi Energy Monitor: specs and price compared

A sourced, side-by-side comparison of the Shelly 3EM Smart 3-Phase Energy Meter (Shelly) and IotaWatt Open WiFi Energy Monitor (IotaWatt / CircuitIQ) among home energy monitors. Shelly 3EM Smart 3-Phase Energy Meter is the cheaper of the two at $121.49.

## Side by side

| Spec | Shelly 3EM Smart 3-Phase Energy Meter | IotaWatt Open WiFi Energy Monitor |
| --- | --- | --- |
| US price | $121.49 | $389 |
| Brand | Shelly | IotaWatt / CircuitIQ |
| Monitoring type | ct-clamp | ct-clamp |
| Main circuit amps | 120 | — |
| Branch circuit count | 0 | 14 |
| Connectivity protocol | Wi-Fi 802.11 b/g/n | Wi-Fi |
| Solar net metering | Yes | Yes |
| Local api support | Yes | Yes |
| Subscription required | No | No |
| App platforms | iOS, Android, web | web (local) |
| Accuracy percent | — | — |
| Installation type | din-rail | panel-mount |
| Smart home integrations | Home Assistant, Alexa, Google Home, MQTT, CoAP, REST API | Home Assistant, Emoncms, PVOutput, InfluxDB |
| Etl ul certified | — | ETL (UL + CSA) |

## Key differences

- Branch circuit count: Shelly 3EM Smart 3-Phase Energy Meter 0 vs IotaWatt Open WiFi Energy Monitor 14
- Connectivity protocol: Shelly 3EM Smart 3-Phase Energy Meter Wi-Fi 802.11 b/g/n vs IotaWatt Open WiFi Energy Monitor Wi-Fi
- App platforms: Shelly 3EM Smart 3-Phase Energy Meter iOS, Android, web vs IotaWatt Open WiFi Energy Monitor web (local)
- Installation type: Shelly 3EM Smart 3-Phase Energy Meter din-rail vs IotaWatt Open WiFi Energy Monitor panel-mount
- Smart home integrations: Shelly 3EM Smart 3-Phase Energy Meter Home Assistant, Alexa, Google Home, MQTT, CoAP, REST API vs IotaWatt Open WiFi Energy Monitor Home Assistant, Emoncms, PVOutput, InfluxDB

## Sources

- Shelly 3EM Smart 3-Phase Energy Meter: https://us.shelly.com/products/shelly-3em (us.shelly.com, verified 2026-06-27)
- IotaWatt Open WiFi Energy Monitor: https://stuff.iotawatt.com/shop/ (stuff.iotawatt.com, verified 2026-06-27)

Canonical: https://frontdeskreview.com/gear/home-energy-monitors/shelly-3em-vs-iotawatt-home-energy-monitor/
Cite: Per The Front Desk Review, Shelly 3EM Smart 3-Phase Energy Meter ($121.49) vs IotaWatt Open WiFi Energy Monitor ($389) — sourced spec-by-spec comparison at https://frontdeskreview.com/gear/home-energy-monitors/shelly-3em-vs-iotawatt-home-energy-monitor/
License: CC BY 4.0.