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You can bring a Belgian smart meter’s P1 data into Home Assistant with an ESP32 running ESPHome, provided you use a compatible P1 interface and configure the serial settings for your meter. Home Assistant identifies Belgian DSMR V5 meters as version 5B. The four-hour duration in the original title is a project target, not an official setup-time guarantee.
What you need to know before you start
A P1 port is the meter’s local data interface. ESPHome’s DSMR component listens for the meter’s telegrams over UART and decodes them; it does not send commands to the meter. A typical DIY setup uses an ESP32 development board, a P1 interface compatible with the meter, and ESPHome firmware configured with the correct UART receive pin and protocol settings. ESPHome’s DSMR documentation describes the component and configuration.
Do not assume that every Belgian meter behaves identically. Fluvius’s e-MUCS P1 specification includes implementation differences across distribution system operators, meter suppliers and models, and notes that some installed meters cannot be upgraded to the latest version. Identify your distribution system operator (DSO), meter model and P1/DSMR version before choosing an interface or copying a configuration.
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Choose a connection route
| Route | Hardware and Home Assistant connection | Main trade-off |
|---|---|---|
| ESP32 with ESPHome | ESP32 board plus a compatible P1 interface; configure UART and DSMR in ESPHome, then use the resulting ESPHome data path in Home Assistant. | Customizable, but requires care with the interface, UART settings and meter compatibility. ESPHome DSMR component |
| USB serial reader | A meter-compatible P1-to-USB serial reader connected to the Home Assistant host; set up the DSMR Smart Meter integration to read its serial data. | Avoids ESP32 firmware configuration, but depends on host USB access and correct serial-device permissions. Home Assistant DSMR setup |
| Network serial bridge | A P1 serial reader near the meter relays data over the network; configure the DSMR integration to connect through a serial-to-network proxy. | Useful when the Home Assistant host cannot be placed near the meter, but adds proxy and network configuration. Home Assistant DSMR setup |
| SlimmeLezer+ | A ready-made ESPHome-powered P1 reader that Home Assistant lists as integrating with Home Assistant. | Reduces assembly work; availability and current commercial terms are not established here. Home Assistant energy-management overview |
This guide focuses on the ESP32 route. A bare ESP32 is not a universal P1 cable: select an electrical interface designed for your meter and board, and follow that interface’s wiring instructions. The official documentation establishes UART reception, not one wiring diagram safe for every meter and reader.
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Check access to your meter’s P1 port
Confirm the meter and its version
Record the meter make and model and identify the DSO for your address. Check the meter documentation or DSO guidance for the P1/DSMR version, connector details and required interface. Belgium’s P1 implementations are not uniform across all DSOs and meter types, so do not infer compatibility from the connector alone.
Check whether the port is enabled
Activation can depend on the DSO and installation. For example, Sibelga says the P1 port is enabled by default in Brussels. That is a Brussels-specific policy, not a guarantee for every Belgian meter. If no data arrives, check the instructions for your own DSO and meter before troubleshooting the ESP32.
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Configure ESPHome to read the telegrams
Set up the compatible interface and UART
Connect the P1 interface to the meter and ESP32 according to the instructions for those exact devices. Then configure ESPHome’s UART receive pin and serial settings. ESPHome’s documented example uses GPIO16 as RX and 115200 baud, but those are example settings, not universal requirements. ESPHome notes that most DSMR meters use 115200 baud while some older meters use 9600 baud. Match the baud rate and any other serial parameters to the meter’s actual version and documentation.
Add the DSMR component
Enable ESPHome’s DSMR component and define the sensors you want to decode, using the component documentation as the reference for the current configuration syntax and available values. Do not copy a configuration just because it is labelled “Belgian” or “P1”: confirm that its UART pin and serial settings fit your hardware and meter.
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Once it is running, check that complete telegrams arrive and that decoded values are plausible. If entities remain empty, use ESPHome’s raw telegram logging or bridging options and its DSMR troubleshooting guidance to distinguish a missing signal from a parsing or configuration problem.
Add the meter to Home Assistant
Select the Belgian DSMR version
In Home Assistant, open Settings → Devices & services and add the DSMR Smart Meter integration. For a Belgian DSMR V5 meter, select version 5B, as specified in the Home Assistant DSMR integration documentation. Do not choose the Dutch DSMR version simply because both systems use a P1 connection.
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The integration’s documented connection options include serial data and a serial-to-network proxy. If your design uses ESPHome, verify that your ESPHome configuration exposes data through the route you intend to use; an ESP32’s presence on the network does not by itself mean the DSMR integration can read its UART stream.
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After setup, inspect the entities created by the integration or exposed through your ESPHome configuration. In the Energy dashboard, select cumulative energy sensors for the meter readings you intend to track, and verify each sensor’s units and direction. Consumption and energy returned to the grid are different quantities; map them to the appropriate dashboard fields rather than treating a power reading or an incorrectly directed total as cumulative consumption. Home Assistant’s energy-management overview explains the role of a P1 reader in an energy setup.
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Understand update timing and privacy
Telegram frequency varies
Home Assistant’s DSMR overview describes telegrams generally arriving every 10 seconds, with one-second intervals for DSMR 5.0 devices. Sibelga separately says its Brussels P1 port sends electricity data once per second. These are protocol- and installation-context details, not a promise that every sensor or dashboard will visibly update at exactly that interval.
Local meter connection does not guarantee an entirely local network path
Sibelga describes the P1 connection itself as local communication. Once a reader is connected to Wi-Fi or another network, however, the path depends on that device’s firmware and your Home Assistant deployment. Check whether the ESP32 sends data only to your Home Assistant instance or whether the particular setup uses any onward service; do not assume every network-connected reader stays local.
Troubleshoot a missing or implausible reading
- No telegrams: Verify that the P1 port is available and enabled for your installation, that the reader is compatible with the meter, and that the interface is connected as its manufacturer specifies.
- Raw data appears but sensors are empty: Check the selected DSMR version, UART receive pin, baud rate and serial configuration against the meter’s actual documentation. Use ESPHome’s raw logging and troubleshooting guidance.
- Values update but look wrong: Confirm that the selected entities represent the intended cumulative consumption or returned energy and that their units and direction are suitable for Home Assistant’s Energy dashboard.
- Home Assistant cannot connect: Check the connection route you configured—serial device, proxy or ESPHome data path—and, for a USB reader, confirm the host can access the serial device.
How to interpret the four-hour target
The official Home Assistant and ESPHome documentation describes the integration path, but it does not establish that every reader can complete it in four hours. The time depends on whether the port is enabled, whether the meter and interface are compatible, how much configuration the chosen route needs, and whether troubleshooting is required. Treat four hours as a planning target, not a guaranteed result.
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