Bosch
Bosch Smart Home Radiator Thermostat II
- Zigbee
Verified September 2026
At around £60-£68 it costs roughly double a SONOFF TRVZB, but you are paying for build quality: precise +/-0.5C regulation and a sturdy valve motor. Bosch quotes under 30dB, and it is quieter than most Zigbee TRVs, though still audible in a silent room rather than truly silent — light sleepers may notice it overnight. It pairs directly with Zigbee2MQTT or ZHA (model BTH-RA, via the QR install code), no Bosch controller required. Fitting is straightforward: it threads onto standard M30x1.5mm valves directly, and ships with Danfoss RA, RAV and RAVL adapters for older UK radiators. Best suited to living rooms and hallways where accuracy matters more than absolute silence.
In Home Assistant
| Control | Type | What it does |
|---|---|---|
| Target temperature | Number (5-30°C) | Set the heating setpoint |
| Valve position | Sensor (0-100%) | Live heating demand / valve opening |
| Boost heating | Switch | Fully open the valve for 5 minutes |
| Remote temperature | Number | Feed in an external room-sensor reading instead of the body-mounted probe |
Zigbee2MQTT exposes a climate entity with heating-demand (valve %) and running-state, plus child lock, window detection, boost-heating and a remote-temperature number input for feeding in an external sensor reading. That remote_temperature value needs pushing at least every 30 minutes or the TRV quietly reverts to its own less-accurate body-mounted probe — worth automating as a push every 15-20 minutes if you want it acting as a true external-sensor thermostat.
Specs
- dimensions
- 87 x 51 x 51 mm (L x W x D)
- battery type
- 2x AA (LR6) alkaline, ~2 years typical life
- zigbee version
- Zigbee 3.0 (model BTH-RA, Zigbee ID RBSH-TRV0-ZB-EU)
- temperature range
- 5-30°C, ±0.5°C accuracy
- valve adapter compatibility
- Fits M30x1.5mm valves directly; Danfoss RA, RAV and RAVL adapters included in box