Home Assistant Energy Monitoring Kit: What You Need, and Where to Buy It in the UK
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The short answer: to monitor your electricity in Home Assistant with a Raspberry Pi and a DIN-rail meter, you need six things: a Raspberry Pi to run Home Assistant, a power supply, a memory card, a case, a MID-approved Modbus energy meter such as the Eastron SDM230, and a USB to RS485 adapter to connect the meter to the Pi. You can buy them separately, or as one kit from one UK supplier: OmniKit's Home Assistant Energy Monitoring Kit (£179.99) has all six, with Home Assistant already installed on the card.
What you need
| Part | What it does | What to look for |
|---|---|---|
| Raspberry Pi | Runs Home Assistant | A Raspberry Pi 4 or 5 runs Home Assistant OS |
| Power supply | Powers the Pi | A DIN-rail power supply sits on the same rail as the meter |
| Memory card | Holds Home Assistant | An industrial or high-endurance card copes better with constant writing |
| Case | Protects the Pi | A DIN-rail case lets the Pi mount next to the meter in an enclosure |
| Energy meter | Measures the circuit | A MID-approved meter with Modbus RS485, such as the Eastron SDM230 for single phase up to 100A |
| USB to RS485 adapter | Connects the meter to the Pi | Takes two data wires from the meter's A and B terminals |
Buying it all from one UK supplier
OmniKit's Home Assistant Energy Monitoring Kit (£179.99) puts everything in one box:
- a Raspberry Pi 4 Model B 8GB in a DIN rail case;
- an Eastron SDM230 MID energy meter;
- a USB to RS485 adapter;
- an industrial power supply;
- an industrial memory card with Home Assistant already installed;
- DIN rail mounting hardware.
The kit is held in UK stock. Order before 2pm on a working day and it is dispatched the same day by Royal Mail Tracked 24, free on UK orders of £39 or more.
Kit or separate parts?
Buying the main parts separately from OmniKit costs more. A Raspberry Pi 4 8GB with DIN rail case is £149.99, the Eastron SDM230 is £36.99 and the USB to RS485 adapter is £15.99. That comes to £202.97 before you add a power supply and a memory card and install Home Assistant yourself. The kit is £179.99 with those included (prices at October 2026).
If you already have a case, power supply and memory card, the Energy Monitoring Starter Bundle (£159.99) gives you the Pi 4 8GB, the SDM230 and the adapter.
Single phase or three phase?
The kit's SDM230 measures one single-phase circuit up to 100A. That covers most UK homes, and single circuits such as an EV charger, a heat pump or a solar inverter. For a three-phase supply, pair a Raspberry Pi with the Eastron SDM72D-M (up to 100A) or the Eastron SDM630MCT with clip-on CT clamps. Our guide Which Eastron meter do I need? explains which.
Fitting and setting up
- An electrician fits the meter and the DIN-rail power supply, because both connect to mains wiring.
- Run two data wires from the meter's A and B terminals to the adapter.
- Plug the adapter into the Pi, connect the Pi to your network, power it up and open Home Assistant in a web browser.
- Add a short Modbus section to Home Assistant's configuration. Our guide How to connect an Eastron SDM230 to Home Assistant has the settings to copy and paste.
- Add the meter's energy readings to Home Assistant's Energy dashboard.
Do you need a meter at all?
If you have a SMETS2 smart meter and only want whole-house figures, a Hildebrand Glow display can pass your smart meter's readings to Home Assistant without any wiring. If you want to monitor without breaking into a circuit, a Wi-Fi clamp meter such as a Shelly is simpler. Our guide Shelly or Eastron for Home Assistant compares them. A MID-approved meter on the circuit is what you need to measure a single circuit accurately or to bill someone for their electricity.
Common questions
Is the kit plug and play?
Not quite. Home Assistant is installed, but once the meter is fitted you add the Modbus connection for it yourself. It's a kit for people building their own Home Assistant system, not a sealed consumer appliance.
Can I bill a tenant from it?
The SDM230 is MID approved, so its readings are accurate enough to charge against. See What does MID approved mean?
Does it need Wi-Fi?
The meter talks to the Pi over two data wires, so the meter itself needs no Wi-Fi. The Pi joins your home network by cable or Wi-Fi.
Raspberry Pi 4 or 5?
Home Assistant runs on both. The kit uses a Raspberry Pi 4 Model B 8GB.
Is there a warranty?
Yes. A one-year OmniKit warranty against faults covers every part of the kit, on top of your legal rights as a consumer.
Questions about your setup? Email customersupport@omnikit.co.uk and we'll help.