The ThermoSphere T-MO (T-MO1) is a smart electric heating thermostat for all direct electric heating systems up to 16A / 3,600W — underfloor heating mats, cables, foil systems and electric towel rails. Connects via Wi-Fi 2.4GHz and Bluetooth (BLE), fits a 35mm deep back box, and is controlled via the T-MO app or LED touch display. Features include ZeroX™ relay technology, active power and energy metering, 2 wired NTC sensor inputs, DirectLink multi-thermostat linking, relay mode for towel rails, OTA updates and an open API for BMS integration. Includes a 3m NTC10K floor sensor probe. UKCA, CE, PSTI certified. 5-year warranty. Colour: White (RAL 9003).
16A
Max Load
Wi-Fi+BLE
Connectivity
84×84mm
Footprint
IP21
Protection
ZeroX™
Extended Life
5 yr
Warranty
Key Features
Wi-Fi 2.4GHz and Bluetooth (BLE) — Works Without Internet
T-MO connects to both Wi-Fi and Bluetooth simultaneously. Bluetooth enables full app setup even with no broadband on site — useful during new builds. Once Wi-Fi is live, the thermostat is controllable remotely from anywhere.
Wi-Fi 2.4GHzBluetooth BLEWorks without internet
ZeroX™ Technology — Extended Relay Lifespan
Proprietary zero-crossing relay switching ensures the relay fires only at the AC waveform's zero point — eliminating the voltage spike that erodes relay contacts over time. Result: a significantly longer thermostat lifespan than standard switching.
ZeroX™Zero-crossing switch
Active Power Metering and Energy Metering
Measures and logs the actual kWh consumption of the connected heating load in real time. Displayed in the T-MO app for running-cost tracking and system verification.
Supports 2 wired sensors simultaneously. Compatible with NTC probes of 6.8, 10 (default), 12, 15, 22, 33, 47 and 100kΩ at 25°C — covering virtually all existing floor probes, making retrofits straightforward. A 3m NTC10K probe is included.
2 sensor inputs6.8–100kΩ3m probe included
DirectLink — Multiple Thermostats Work Together
DirectLink sends mode and setpoint wirelessly from one T-MO to linked units — ideal for open-plan multi-zone spaces or syncing schedules across rooms.
DirectLinkMulti-zone sync
Relay Mode — Schedules Electric Towel Rails
T-MO operates as a scheduled on/off relay without temperature sensing — perfect for controlling electric towel bars where only timing matters.
Relay modeTowel rail control
OTA Updates and Open API for BMS Integration
Over-the-air firmware updates add features without manual intervention. The open API enables integration with building management systems (BMS) and third-party smart home platforms.
OTA updatesOpen APIBMS compatible
ThermoSphere Remote Commissioning — Zero Callbacks
Grant ThermoSphere temporary access via the app after installation. Their team remotely sets up the schedule, optimises settings and briefs the homeowner — the installer walks away after wiring.
ℹ Installation: All electrical connections must be made by a qualified electrician in accordance with BS 7671. Register your product with ThermoSphere online to activate your lifetime warranty.
Frequently Asked Questions
Does the T-MO work without a Wi-Fi connection?
Yes. T-MO connects via Bluetooth as well as Wi-Fi. Bluetooth enables full app configuration even without broadband on site. The LED display also gives basic on/off and temperature control without any app.
What floor sensors are compatible?
NTC probes of 6.8, 10, 12, 15, 22, 33, 47 and 100kΩ at 25°C. Default is 10kΩ. Measure your existing probe with a multimeter to confirm compatibility before replacing a thermostat.
How does remote commissioning work?
After wiring, the installer connects T-MO to Wi-Fi and grants ThermoSphere temporary access in the app. ThermoSphere remotely programmes the schedule, checks sensors, optimises settings and contacts the homeowner. The installer leaves immediately after the electrical connection.
What is the maximum cable cross-section?
2.5mm². Use ferrules on stranded cable. Maximum terminal torque: 2 Nm.
What is the difference between the white and black T-MO?
The two models are identical in specification. The only difference is finish colour. Choose whichever suits your room and décor.
Can T-MO be used for non-heating applications?
In relay mode it functions as a scheduled on/off switch for any resistive load up to 16A — electric towel rails, mirror demisters etc. No temperature sensing needed.
Related Products
ThermoSphere T-MO Thermostat — Black
Same thermostat, black finish (T-MO2)
ThermoSphere Mesh 150W/m² UFH Mat
Compatible heating system — tile and stone floors
ThermoSphere Foil 140W/m² UFH
Compatible — wood, carpet and vinyl floors
ThermoSphere Electric Towel Bars
12V SELV towel bars controlled via T-MO relay mode
BTU & WATT Calculator
Room Dimensions
Room Type
Living Room
Bedroom
Kitchen
Bathroom
Conservatory
Hallway
Glazing Type
Single Glazed
Double Glazed
Triple Glazed
External Walls
0 Wall
1 Wall
2 Walls
3 Walls
4 Walls
Insulation Level
Poor
Average
Good (New Build)
Required Heating
0
Watts
0
BTUs
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