Electricity monitoring: see where your home’s energy actually goes

Every month the energy bill arrives as a single number. You know how much the house used, but not where it went. The water heater, the bedroom AC, the old fridge in the utility room, the oven, the computer that never sleeps. It all collapses into one figure that doesn’t tell you what to change.

Electricity monitoring breaks that number apart. Instead of seeing only the whole-house total, you see how much each circuit uses, hour by hour. With that information you make concrete decisions—not guesses.

How you measure each circuit

The most common approach in an existing home is clamp-style current sensors, known as CTs (current transformers). They’re rings that open and close around a wire. You don’t cut anything or disconnect the circuit: the clamp wraps the conductor and measures the current from the magnetic field it produces.

Those clamps sit inside the electrical panel—one on each circuit you want to measure—and connect to a small metering module. The module combines current with line voltage, calculates power, and sends the data to the house. Many of these modules use an ESP32 inside, the same chip we use in other projects, and they integrate with the home server.

One rule with no exceptions: everything that goes inside the panel is installed by a licensed electrician. Even though the clamps don’t require cutting wires, you’re working next to live conductors. We design the system, decide what to measure, and wire it into your app; a licensed electrician does the panel work.

What’s worth measuring

You don’t need a clamp on every breaker. Focus on the circuits that use the most power or the ones you keep wondering about.

1. The main feed. A clamp on the incoming service gives you real-time whole-house use, not only the month-end total.
2. The water heater. In many homes it’s one of the biggest loads.
3. Air conditioners. Each minisplit on its own circuit, so you can compare rooms and schedules.
4. The kitchen. Oven, electric range, dishwasher.
5. Washer and dryer.
6. The study or rack outlet circuit, where gear that never turns off often lives.

For individual appliances without their own circuit, a smart plug with energy metering fills the gaps. Those plugs are also mains-powered devices, so they strengthen the home’s mesh network, as we explain in the Zigbee and Thread guide.

If you’re remodeling, design the panel with this in mind

A remodel is the best time to get this right from the start. With the panel open and circuits still being defined, you can make choices that cost far more later.

Separate circuits for big loads. If the water heater, each AC unit, and the kitchen each have their own circuit, measuring each one is straightforward. If everything is mixed across a few breakers, the data tells you less.

Space in the panel. The clamps and metering module need room. A panel a bit larger than the bare minimum leaves space to grow without crowding the wires.

Breakers with built-in metering. Some breakers and panels already measure per circuit and talk to the home network. Before buying, we check that they speak an open protocol and work without depending on a manufacturer’s cloud. If a device only works with its own app and account, we don’t recommend it.

Circuits you’ll want to shut off. If you know you’ll want to cut a circuit from the app—for example the water heater at night—plan for a contactor or relay sized for that load. Again, an electrician installs and sizes that.

Thinking about the panel this way during design costs little. Doing it later means opening things up, reorganizing, and sometimes replacing the whole panel.

How it helps you use less

Seeing use by circuit changes how the house is run—not because someone lectures you, but because the data makes it obvious.

You find the load nobody notices

The first discovery is almost always base load: what the house draws at three in the morning, when nothing should be happening. An old fridge, a forgotten dehumidifier, devices in standby. That load runs 24 hours a day, every day, and without metering it’s invisible.

You compare before and after

You replace a fridge, adjust the water heater temperature, or swap bulbs. With metering you know whether the change worked and by how much. Without it, you wait for the bill and guess.

You decide what to turn off and when

When you see the water heater drawing power in hours when nobody showers, scheduling it stops being a vague idea and becomes an obvious rule. Same for a room AC left on with nobody inside, or a rack that could sleep at night.

The house can take some of those decisions on its own. Turn off the water heater between midnight and five. Warn you if a room’s AC has been on for hours while the contact sensor says the window is open. Cut standby gear in the study when you activate “away” mode.

A greener home without giving up comfort

Using less energy doesn’t have to mean living with less. Most of the savings come from things that weren’t helping anyway: appliances left on unused, old equipment that draws too much, bad schedules. Measuring lets you remove that and leave what you actually enjoy intact.

What you’ll see in your app

Consumption data shows up in your app alongside the rest of the house. A view of total use right now. A list of circuits with what each used today, this week, and this month. And hourly charts to spot patterns—like the morning water-heater peak or the bedroom AC at night.

You can also get useful alerts: a circuit drawing far more than usual, a fridge suddenly working twice as hard, or base load rising for no clear reason. Sometimes that alert is the first sign an appliance is failing.

How we do it in your home

We work with what you already have. If your panel has space and circuits are well separated, we add the clamps and metering module, and a licensed electrician handles the install. If your home already has metering plugs or a meter that speaks an open protocol, we integrate them. We only replace what won’t cooperate.

If you’re remodeling, we get involved early: we review the electrical design with your electrician so the panel and circuits are ready to measure and control.

Everything ends up in your own app, built for your home, with no subscription and without your consumption data living in someone else’s cloud. Monitoring rides on the same network that supports the rest of the house, so if you want to understand how it all connects, the starting point is our Zigbee and Thread guide.