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ThermoSphere Bluetooth Programmable Thermostat 16A

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ThermoSphere presents you with The Bluetooth programmable thermostat (BT21) which is the fastest, simplest and easiest thermostat to set up and program. Ever!


The setting up of The Bluetooth programmable thermostat (BT21) is easy. You can set up a heating schedule on the BT21 Bluetooth programmable thermostat just use the app and you are done in 60 seconds! 

TAP AND TWIST: At first glance, you could be mistaken the BT21 for a manual thermostat but there is more to it than meets the eye. 

So, what’s the waiting for dial? Just ‘tap’ and ‘twist’ it to adjust the Comfort and Eco modes. Everything else is done on the app!

COPY AND PASTE: The setting up of the BT21 thermostat is easy. You can set up one thermostat and then copy and paste the settings and heating schedule to the rest.      

LOCKDOWN MODE:  There is no need to worry if family members adjust the temperature on the dial. With the lockdown mode, you can make the dial completely tamper-proof just by using the feature on the app. 

NOT JUST FLOOR HEATING: The BT21 thermostat is packed with a lot of features that make this thermostat one of the most dynamic thermostats in all of your around. Not just floor heating you can control your electric towel bars also with it. The BT21 also can do that! 


The manual dial is being used to adjust the temperature of the eco and comfort modes, everything else is done on the app! Fear not! You can lock the dial to stop wandering hands adjusting the temperature when you are not looking. 


The app for the BT21 Bluetooth programmable thermostat is a powerhouse of functionality. You can create heating schedules in under 60 seconds and adjust all settings easily without navigating through complicated menus.    


There’s no internet. No hubs. No worries. The power of Bluetooth of BT21 will make you worry less. Unlike thermostats that rely on WiFi signals, you‘ll have peace of mind knowing that the BT21 uses only Bluetooth connectivity. It also means you don‘t waste time remembering passwords. Just connect and go!


‘Beautiful things that make your life better’ is a Scandinavian concept that has always been highly regarded. It’s Designed and made in Scandinavia, and the BT21 takes this concept to a new level that will help you live well. 

There are also have some things that you might have asked : 

Does the BT21 thermostat connect to the internet?

  • No. The BT21 uses Bluetooth to connect to your phone so there is no internet connection. That makes connecting easy and reliable with no routers, hubs, passwords, or wires.   

Is Bluetooth connectivity secure?

  • Bluetooth is one of the most secure wireless connections to use and more secure than WiFi. It also means you don‘t waste time remembering passwords or worry if your internet goes down. 

Do I have to be at home to work it?

  • Yes, you do! You have to confirm any changes made in the app by turning the dial. This is a security feature that means nobody else can tamper with your thermostats.

Can I stop people manually adjusting the temperature?

  •  Lockdown Mode disables the dial and SET button on the thermostat to prevent tampering. You can unlock it with a pin code in the app. When lockdown mode is on, your thermostat will run the heating program as normal.

Can I use the BT21 as a manual thermostat?

  • Yes, you can! Simply use the dial to set the temperature that you want your heating to get to and the thermostat will maintain that temperature until you change it. It is best to use Comfort mode for this application. However, we recommend using the BT21 app to set up a simple heating schedule that will save you money on your heating bills and help the environment by using less energy.

What is the Bluetooth signal range?

  • You should be able to view your thermostat from around 10-15m away in most homes. But you have to be standing next to the thermostat to confirm changes so best to get up and have a little walk over to your thermostat.

Is it Lot20 Compliant?

  • Of course! What is this, 2019? J The BT21 actually has the best possible EcoDesign score (40%) so you won‘t find a more efficient thermostat.

230V AC 50Hz
Maximum Load:
Bluetooth 4.2
Ambient temperature:
+5°C - +35°C
Protection rating:
IP21 (Safe in bathrooms outside zone 2)
86 x 86 x 10mm
25mm deep back box
Included sensors:
Built in ambient External NTC10K floor sensor
Also works with:
NTC 2k, 12.5k, 15k, 33k sensor probes
3 years
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