Home Assistant Energy Monitoring: Track Every Watt in Your Home

Why Monitor Your Home's Energy?

The average household spends $1,500–$2,500 per year on electricity, yet most people have no idea which appliances are driving those costs. Home Assistant's energy monitoring features change that completely. Instead of waiting for your monthly bill and guessing, you get real-time visibility into every watt flowing through your home.

Energy monitoring in Home Assistant can tell you how much power your HVAC system, EV charger, water heater, or that old fridge in the garage is actually consuming — in real time, historically, and broken down by cost. For most people, the first month of monitoring reveals at least one major energy waster they didn't know about.

The HA Energy Dashboard

Home Assistant introduced a built-in Energy Dashboard in version 2021.8. It's now one of HA's most polished features. You'll find it at Energy in the left sidebar (or go to Settings → Dashboards → Energy).

The dashboard provides:

• Daily, weekly, and monthly electricity consumption graphs
• Cost tracking (enter your tariff rate in Settings → Energy)
• Grid consumption vs. solar production vs. battery
• Individual device breakdown (when device sensors are configured)
• Gas and water usage (if you have sensors for those)

To populate the dashboard, you need energy sensors that provide data in kWh (kilowatt-hours). Instantaneous power readings in watts are useful for monitoring, but the Energy dashboard specifically requires cumulative energy sensors.

Whole-Home Monitoring

The most comprehensive approach is monitoring your entire electrical panel. This gives you total home consumption data, and when combined with smart plugs on individual circuits, you can break down usage by appliance.

Smart Utility Meters

If your utility meter supports it, the P1 port (common in Europe) or an optical reader can pull data directly from your meter with sub-minute resolution. HA has excellent integrations for these via the DSMR add-on or Slimme Meter integration.

In the US, many utilities now offer API access to smart meter data through programs like Green Button. The Sense energy monitor is a popular option that clips onto your electrical panel and uses machine learning to identify individual devices — it integrates with Home Assistant via HACS.

CT Clamp Monitors

Current transformer (CT) clamp monitors are the most flexible whole-home solution. They clip around your electrical cables (no wiring changes required) and measure current draw. The Shelly EM is the most popular choice for Home Assistant users — it's affordable, has native HA integration, and supports two CT clamps for monitoring two circuits independently.

Device-Level Monitoring

Beyond whole-home monitoring, you can add energy monitoring at the device level using:

• Smart plugs with energy monitoring — TP-Link Tapo P115, Shelly Plug S, or Sonoff S31 for individual appliances
• Smart power strips — Monitor multiple devices at once
• Zigbee energy monitoring plugs — Integrate directly without cloud dependency
• Built-in device reporting — Many modern appliances report energy via their native integrations (e.g., Tesla, some EV chargers)

Once you have energy sensors set up, you can add them to the HA Energy Dashboard under Settings → Energy → Add Individual Devices.

Shelly EM Setup for Home Assistant

The Shelly EM is a standout product for whole-home or circuit-level monitoring. It mounts inside your electrical panel (or in a DIN rail enclosure) and uses CT clamps to monitor up to two circuits without any direct electrical contact.

Hardware Installation

1. Turn off the circuit you're monitoring at the breaker (the Shelly EM itself connects to a live 110/240V feed — if unsure, hire an electrician)
2. Clip the CT clamps around the hot wire(s) of the circuit(s) you want to monitor
3. Connect the Shelly EM to a 24V AC adapter (included) or directly to a 110-240V feed
4. Power on and connect to its Wi-Fi AP for initial configuration

Home Assistant Integration

The Shelly integration is built into Home Assistant (no HACS required). Once the Shelly EM is on your network, HA will usually auto-discover it. If not, go to Settings → Integrations → Add Integration → Shelly and enter the device's IP address.

The integration provides real-time power (W) and cumulative energy (kWh) sensors. Add the kWh sensors to the Energy Dashboard and you're done.

Adding Solar Production

If you have solar panels, Home Assistant can show your production data alongside consumption, giving you a complete picture of your energy flow. Most solar inverters have HA integrations — popular options include SolarEdge, Enphase, Fronius, and Goodwe.

Once integrated, add the solar production sensor to the Energy Dashboard under "Solar Panels." HA will then calculate your self-consumption rate, grid exports, and net energy cost. If you have a home battery (Powerwall, Huawei LUNA, etc.), add that too for a complete energy flow visualization.

Energy-Based Automations

The real power of energy monitoring comes when you use the data to automate decisions:

• Shift loads to off-peak hours — Start the dishwasher automatically when electricity is cheapest (works great with dynamic tariff integrations like Octopus Energy)
• Alert on high consumption — Notify if total home consumption exceeds a threshold (helps catch appliances left on)
• Solar excess automation — Turn on the pool pump, water heater, or EV charger when solar production exceeds home consumption
• Standby vampire hunting — Alert when a device that should be off is still drawing power

Tips to Reduce Your Bill

Once you have data, the insights often pay for the monitoring hardware within a month or two:

• Identify always-on appliances drawing phantom load (old TVs, cable boxes, game consoles in standby)
• Compare your HVAC's energy use across temperature settings to find the sweet spot
• Track your EV charging cost separately from home consumption
• Find appliances that run longer than expected (old refrigerators, inefficient dryers)
• Use historical data to see the impact of insulation or appliance upgrades