Case study

Home Assistant

IoT · Home automation · Real-time data

After the meter, I needed the appliances. Home Assistant + Zigbee plugs give per-outlet measurement, locally, no third-party cloud. And an unexpected blind spot.

Role

Integrator & ops

Stack

Home Assistant · Zigbee2MQTT · Mosquitto

Status

In production

From total to per-appliance

LinkyStat gives seven years of history. Total consumption is falling. But I have no idea what's actually using the power. Heaters dominate — I can feel that. But the water heater? Everything else?

I wanted per-appliance measurement. And a proper platform, not a brittle script. The Home Assistant community stands out: massive ecosystem, fully local, not a byte sent to a third-party cloud.

Home Assistant dashboard: live power, room temperatures, and energy donut with dominant untracked consumption

FIG. 01 My Home Assistant dashboard in production.

What HA brings

Per-outlet measurement, real-time

Each Zigbee plug reports instantaneous power and full history. The HA energy dashboard centralises and visualises it.

Free ground-truth data

The plugs become a continuous ground truth: precise labels on every appliance, no manual annotation. This will matter later.

Local automations

Schedules, presence detection, scenes. Everything runs locally — no cloud dependency, no external single point of failure.

Active community

Thousands of maintained integrations. Zigbee2MQTT, Mosquitto, ESPHome, Lovelace cards: each brick is documented and actively supported.

The problem

Home Assistant energy donut with dominant untracked consumption slice — The HA energy donut: the 'Untracked consumption' slice accounts for almost 50% of the total.

The dashboard is accurate, for what it can see. TV, laptop, fridge, oven, router: all measured at the outlet.

But Untracked consumption accounts for almost 50 % of the total. Nearly half my bill, unlabelled.

The prime suspect: the water heater. A fixed appliance, wired directly into the circuit, no way to put a smart plug in line. And yet it's probably my biggest single cost.

The question raised

Almost 50 % untracked. Mostly the water heater, my biggest cost, impossible to wire directly.

But the Linky meter's aggregate curve sees it. Every water heater activation leaves a trace in the aggregate signal.

Can that signal reveal the appliances we can't measure? That question became Linkya.

See the NILM approach →

References

[01]
Home Assistant
The reference open-source home automation platform. Fully local by default, massive integration ecosystem, very active community. The right choice for a serious homelab.
[02]
Zigbee2MQTT
Zigbee-to-MQTT bridge, no third-party cloud. Supports hundreds of devices including energy-monitoring plugs that give the per-outlet ground truth.
[03]
Mosquitto
Lightweight open-source MQTT broker. The message bus between Zigbee plugs, Zigbee2MQTT and Home Assistant.