Smart thermostat

Smart radiator thermostat II

Flexible operating options ensure efficient heating and comfortable room conditions

Smart thermostat

Smart thermostats – heat your home the modern way

Turning radiators up and down was yesterday! Control your heating effortlessly and precisely via app – wherever you happen to be. With your Smart Home radiator thermostat, you can heat your home more conveniently and more efficiently. For the environment and your pocket.

Keep track of
the temperature

With your smart thermostat, you can adjust the temperature in each room individually to the nearest half a degree and can keep track of current temperatures at any time via the app.


The Smart Home radiator thermostat makes it easy to save energy: Thanks to time programs and clever services such as “Sustainable ventilation”, you can heat your home just enough to feel comfortable.

Combined room temperature

A number of smart thermostats within a room can be combined in the app to give an overall room temperature and controlled in groups – optionally particularly precisely with a room thermostat .

Control heating flexibly – via voice, app etc.

Whether you use Alexa, Google Assistant or Siri in the Apple HomeKit® – your Bosch Smart Home radiator thermostats can easily be controlled via voice commands:

“Alexa, set the temperature in the living room to 22 degrees.”

In addition to voice commands, there are many other ways to regulate your smart radiator thermostats:

  • By pushing and turning the knob on the device
  • Via the app – at home or when you are out
  • Via automations – with the IF/THEN principle
  • Via time programs – individually for each room
  • Via custom scenarios – to group together several Smart Home thermostats/devices

Sustainable ventilation saves energy

The pre-configured “Sustainable ventilation” service is the star among the fully automatic control systems for smart thermostats. It links your door/window contacts to the heating control system:

If your door/window contact detects that a window is open, the smart radiator thermostats automatically turn down the heating in the room – this is also possible after an individually adjustable delay, e.g. if you only open your windows briefly to let your cat out.

Your device lights up blue and red to show you the start and end of the heating break during ventilation.

This way, none of the heat goes out the window and you save energy.

The color indicates the heating status

Not only the link to your Smart Home system makes your heating thermostat smart – it stands out from conventional devices in design terms too:

Thanks to its compact size (87 x 51 x 51 mm (LxWxD)) and swivelling display, it fits discreetly into your living room – either horizontally or vertically mounted.

The high-contrast display with background lighting guarantees optimum legibility whatever the lighting conditions are.

Practical: The light ring with multicolored LEDs can be seen from all angles. It indicates actions performed and the status of the thermostat.

Using the child lock

Children’s hands on radiator thermostats often lead to incorrect settings and wasted energy. But there is no need to sweat (or freeze) as a result:

Specify in the app or using the operating button on the device that manual settings on the device itself are no longer possible.

This way, kids cannot adjust anything on the smart thermostats – and you can still control the room temperature conveniently via app, voice assistant or room thermostat .

Protective functions you can rely on

Could you be left in the cold if your heating breaks down? Not in a smart home! Your radiator thermostats feature a number of protective functions to minimize the risk of a breakdown:

  • Frost protection: Prevents damage to radiators owing to open windows or unused rooms.
  • Limescale protection: To prevent limescale from forming in your thermostats outside the heating period, the valve opens briefly once a week throughout the year.
  • Battery warning: If the two AA batteries which can easily be replaced are getting low, you will be given a warning via app several weeks in advance so that you can replace them in good time.
  • Breakdown warning: Do you want to be on the safe side? You can also create an “IF room temperature <15° THEN send message” automation.

Easy to install

There is no need to be a heating expert to make your radiator thermostats smart.

Bosch Smart Home thermostats can be installed quickly and easily without a fitter – the step-by-step instructions in the app guide you through the assembly process and, thanks to the two AA batteries supplied, your thermostat is ready for use straight away.

The smart thermostats fit almost all radiators: Either directly with M30 x 1.5 mm screw threads or with the help of the adapters supplied (Danfoss RA, Danfoss RAVL).

Our adapter check will tell you if you need an adapter.

How it works

Set individual time programs

Set individual time programs

Would you like to get out of bed in the morning and go into a preheated bathroom – without having the heating running all night?

Heating systems that turn themselves down automatically during work hours – then make sure the house is warm when you come home?

The Bosch Smart Home radiator thermostats’ individual heating plans make this possible:

They determine when your heating will be on or off – individually for each day of the week.

Naturally, you can interrupt your heating plans at any time in order to set an alternative temperature.

Integration into scenarios and automations

Integration into scenarios and automations

Your smart thermostats are linked to your entire Smart Home system. They can therefore be integrated effortlessly into individual scenarios or automations:

  • In scenarios, you can control several devices at the same time with a single command. For example, your “Leaving home” scenario turns down all your radiator thermostats automatically, turns out the lights and switches off the power to devices connected to smart plugs.

  • With automations, you can connect your smart radiator thermostats to other devices to control these according to the if-then principle.You can use temperature measurements to automatically lower your smart shutters from a certain temperature to keep out the heat – or to switch on fans connected via smart plugs for cooling. Conversely, smart devices can also activate your thermostats. The heating in your office could then be turned on automatically when you switch on the light to start work.

Sustainable ventilation

Sustainable ventilation

The preconfigured “Sustainable ventilation” service turns down your Smart Home thermostats as soon as your door/window contact detects an open window in the room. You will find it under “Services” in the “Climate manager”.

Naturally, you can adapt the service to meet your individual requirements:

  • Select door/window contacts which will act as a trigger for regulating the thermostats.

  • Select a reaction time (0-180 seconds) after which the radiator thermostats will be turned down. This time delay allows you to let your cat out for example without your smart thermostats being turned down immediately.

Define a heating break

Define a heating break

A “heating break” is practical in summer and if you are away for long periods.

In this mode, your smart radiator thermostat is automatically turned down to the lowest setting and the room control which is part of automations and scenarios is ignored for the duration of the heating break. Consequently, there is no need to change all your automations and scenarios in summer.

To prevent limescale in the radiator valves building up over time, they are opened regularly even during the heating break.

Your radiator valves are thus maintained all year round without having the heating on unnecessarily.

You will find the heating break option in your Bosch Smart Home app under “Services” > “Climate manager”“ > “Heating break & cooling”.

Manual control

Manual control

Manual control on the device itself is intuitive and simple:

  • Set desired temperature: Press the control knob on your smart thermostat briefly (1 second). The menu (“SET”) will open. You can now increase or decrease the temperature in 0.5 degree increments by turning the knob towards + or -.

  • End heating break: Maybe a “heating break” is activated for your smart radiator thermostat but you would now like to heat the room. To do this, press the control knob for 1 second. You can now set your desired temperature in the usual way.

  • Activate/deactivate child lock: To activate or deactivate the child lock, press the control knob for 3 seconds until “LCK” appears. By turning the knob towards + or -, you can easily activate or deactivate the child lock.

Buy now

radiator thermostat II

radiator thermostat II
radiator thermostat II
radiator thermostat II
radiator thermostat II
radiator thermostat II
radiator thermostat II
radiator thermostat II
radiator thermostat II
radiator thermostat II
radiator thermostat II
radiator thermostat II
radiator thermostat II
radiator thermostat II
radiator thermostat II
radiator thermostat II
Allows individual temperatures in each room and shows the values in the app
Time programs and smart services help you to save energy when heating your home
Other radiators can be grouped together to give an overall room temperature
Can be controlled flexibly – via voice commands or when you are out
Temperature adjustable in 0.5-degree increments – via app or intuitively on the device by turning/pushing the knob
Can only be used in combination with the Bosch Smart Home controller
70.95 GBP
* Including 20% VAT

*Important note: The radiator thermostat II is not compatible with Bosch EasyControl.

Further information

Technical Data

Device type designation
Part Number
Protection class
Ambient temperature
0 °C … + 50 °C
10 % … 80 %
Housing dimensions (W × H × D)
51 × 51 × 87 mm
Weight (without batteries)
135 g
Radio frequency band
2.4 – 2.4835 GHz
Radio protocol
ZigBee 3.0
Max. transmitting power
3 mW
Radio range in the open
< 50 m
Software class
Receiver category
2 × LR6/Mignon/AA (alkaline)
Battery lifespan (typical)
< 2 years
Degree of soiling
Mode of operation
Valve connection
M30 × 1.5 mm
Max. power consumption
220 mA / < 0.8 W

Box contents

  • 1 radiator thermostat BTH-RA
  • 2 AA batteries
  • 1 Danfoss RA adapter
  • 1 Danfoss RAVL adapter
  • 1 User manual in 11 languages
Notes about battery disposal

In conjunction with the sale of batteries or supply of devices that contain batteries, we are obligated to point out the following:

Used batteries should not be disposed of in the household rubbish. Consumers are obligated to take batteries to a suitable collection point provided by retailers or municipalities.

The symbols on the batteries have the following meaning:

The symbol of the garbage can crossed out by an X means that the battery must not be disposed of in household waste.

Pb = Battery contains more than 0.004 percent lead by mass, Cd = Battery contains more than 0.002 percent cadmium by mass, Hg = Battery contains more than 0.0005 percent mercury by mass

Please note the instructions above.

Download now

Bosch Smart Home App

Download the Bosch Smart Home App in your Apple App Store or Google Play Store.