Monitoring energy usage with smart plugs, Prometheus and Grafana

Original Article ↗ Hacker News Discussion ↗

Home Assistant vs. Custom Monitoring Stacks

  • Many argue that Home Assistant (HA) already provides energy monitoring, graphs, and automations “out of the box,” making Prometheus+Grafana overkill for basic home use.
  • Others report bad experiences with HAOS / supervised Docker setups (laggy UI, failures that are hard to debug inside containers) and prefer traditional package-managed installs or NixOS-style deployments.
  • There’s tension around HA’s distribution philosophy: some see containers as a reproducible “stable state,” others dislike being locked into a bespoke mini‑distro and perceive hostility toward third‑party packaging (e.g., NixOS).
  • Several note that HA Core / Container now exist as more flexible options, but mistrust remains for some users who prefer “MQTT-first” architectures and separate logging/automation stacks.

Grafana, Automation, and SCADA Direction

  • Grafana is praised for deeper analysis, aggregations, and comparisons versus HA’s “at a glance” graphs, especially by off‑grid users.
  • Some run both: HA for device integration and automations; Prometheus/Influx + Grafana for serious visualization.
  • A Grafana developer mentions ongoing work to push Grafana toward IoT/SCADA control via “data sinks” (e.g., HTTP, MQTT, Modbus) and interactive Canvas panels; others suggest looking at Node‑RED’s ecosystem as inspiration.

Protocols and Network Choices

  • Several recommend Zigbee or Z‑Wave plugs over WiFi for scale and reliability; others report 20+ WiFi/ESP devices working fine, especially when 2.4 GHz is reserved mostly for IoT.
  • Debate exists over whether WiFi unreliability is due to cheap devices, poor RF environments, or infrastructure issues.
  • Powerline networking is criticized for RF noise; some reminisce about older powerline/X10 control being simple and robust.

Hardware Choices, Calibration, and Safety

  • Many plug recommendations: Shelly, Athom (ESPHome/Tasmota), TP‑Link/Tapo, Innr, Robb, ThirdReality, IKEA, Gosund, various Zigbee outlets, etc.; experiences vary, including premature failures on some cheap brands.
  • Calibration of Tasmota/ESPHome power monitoring is raised; others rely on vendors claiming “pre‑calibrated.”
  • Strong warnings against cheap AliExpress main‑breakers and relays being used at full rated current; CT clamps and dedicated monitors (Emporia Vue, IoTaWatt, Shelly 3EM) are seen as safer for whole‑home or high‑amp circuits.
  • Overvoltage behavior differs by brand and may conflict with local grid conditions, requiring automations to recover tripped devices.

Whole‑Home and Utility‑Based Monitoring

  • Approaches include: multi‑CT panel monitors (Emporia Vue, IoTaWatt), Zigbee breakers, smart‑meter interfaces (P1/HAN/DLMS readers, vendor dongles, Eagle gateways), and DIY ESP32 sensors on meter LEDs/disks.
  • Some countries’ utilities provide hourly or near‑hourly consumption data via portals; others only offer coarse, delayed summaries, driving interest in local monitoring.