ThermoSphere Bluetooth Programmable Thermostat BT21

The ThermoSphere BT21 Bluetooth Programmable Thermostat offers intuitive manual controls together with app-based programming for electric underfloor heating. Its simple manual dial and Bluetooth app enable fast setup, tailored scheduling, and effortless temperature adjustments in both new and retrofit installations. Feature highlights include immediate Eco/Comfort mode changes, wide sensor compatibility, modern discreet design, and reliable Bluetooth connectivity—no Wi-Fi required.

Key Features

• Bluetooth control via free app—no internet or smart hub needed
• Manual dial for quick Comfort/Eco adjustments; lockable for security
• Easy, quick scheduling directly on your phone
• Compatible with most common floor sensor probes
• Fits UK standard 25mm back box; simple retrofitting
• IP21 rated for safe use in most rooms
• 3-year manufacturer warranty

Technical Details

• Model/MPN: BT21
• EAN: 5056257307480
• Voltage: 230V AC, 50Hz
• Switching Output: Max 16A resistive (up to 3,600W)
• Temperature Range: 5°C to 40°C (settable)
• Sensors Included: 2 x NTC floor probes (with 3m cable)
• Compatibility: Works with most industry-standard floor probes (NTC type)
• Mounting: Fits UK 25mm single pattress or back box
• Dimensions: 86 x 86 x 10mm (front face depth from wall)
• Protection Class: IP21 (suitable for zone 3 and non-wet room locations)
• User Interface: Dial control with lock option, two touch buttons, Bluetooth app support (iOS/Android)
• Operating Modes: Programmable, Comfort, Eco, Manual, Frost protection
• Warranty: 3 years (manufacturer)
• Certification: CE marked, compliant with relevant UK/EU standards
• Wireless Protocol: Bluetooth Low Energy (works up to standard room distance between phone and thermostat)

Other Details

• Supplied with two external floor sensor probes
• Can be used as a manual or programmable thermostat
• Designed for electric underfloor heating but generally compatible with other electric heating systems
  

Why Choose the ThermoSphere BT21?

This thermostat uniquely combines the convenience of Bluetooth setup and control with classic manual functionality, making floor heating scheduling easy for any user or project. Its broad compatibility, secure operation, and robust build quality make it a top choice for efficient underfloor heating control in residential and commercial settings.