I got a new smart gas meter fitted and wanted real gas consumption monitoring in Home Assistant. I checked the meter model, its label and the install paperwork before touching SDR gear. That saved time. If you want reliable readings, start with what the meter actually speaks, not with guessing at antennas and containers.
Most modern meters in the UK and Europe use a radio interface such as Wireless M‑Bus. It often runs around 868 MHz for smart metering. I found recent product notes and RF module vendors showing Wireless M‑Bus support at those bands, which explains why many DIY SDR attempts focus there (Quectel/STACKFORCE announcement, Radiocrafts module note). Make sure you read the meter label or ask the installer which protocol and frequency your meter uses. If the meter lists a vendor protocol, model number, or RF spec, you now have the most useful clue for integration.
If your meter does broadcast on a common RF protocol, try passive capture with rtlsdr. I have used containers running rtlsdr plus metermon and rtl433. Start with a good antenna tuned for the target band and set a wide scan across 433 MHz and 868 MHz. Place the dongle near an external wall or window, not tucked in a metal cabinet. Run a long capture during peak usage, for example while heating or cooking, so the bursts are more likely to appear. If you get packets, metermon or rtl433 can decode common meter formats. If nothing shows, change antenna, move the dongle closer to the meter, then increase capture time. For battery‑powered meters the transmissions can be sparse, so patience matters.
Radio decoding is not always the right route. If the meter exposes a pulse output junction, a pulse reader is the simplest and most robust option for gas consumption monitoring. I clipped a small optocoupler or reed switch to the pulse terminal and fed it into a microcontroller that publishes MQTT to Home Assistant. That gives immediate, high-resolution readings and works with automation and energy dashboards. Optical reading with a cheap camera aimed at the meter dial or LED pulse is another option when access to wiring is restricted. Some vendors provide an API or a gateway that publishes readings; contact the utility to ask if an AMI gateway or API exists for your meter model. If the meter uses a proprietary vendor cloud, check whether the vendor has an open API, or whether the community has written an integration for Home Assistant.
Set up Home Assistant sensors once you have a data feed. For MQTT, publish the pulse counts and create a sensor that converts pulses to cubic metres. For decoded RF messages, push the parsed payload into MQTT or the Home Assistant REST API. I recommend keeping raw packet dumps while you test so you can reprocess them if the decoder misses fields. For automation, use sensor templates to calculate instantaneous flow and cumulative consumption, then drive automations for alerts or cost tracking.
Concrete takeaways: read the meter label first, then decide on radio capture or a physical pulse feed. If you go the rtlsdr route, focus on the correct band, use a proper antenna and long captures, and try rtl433 and metermon before assuming the meter is invisible. If radio fails, pulse readers, optical readers or vendor APIs usually work and plug cleanly into Home Assistant for gas consumption monitoring and automation.
