Control From Anywhere
Use the MyThermowatt app to manage compatible water heating systems remotely, adjust settings and stay connected to your hot water.
SMART HEATING CONTROLS & RETROFIT TECHNOLOGY
Make Your Existing Hot Water System Smarter.
Discover how connected immersion heater controls and Wi-Fi technology can bring greater flexibility, intelligent scheduling and smarter hot water management to compatible existing systems — without automatically replacing the entire water heater.
Discover connected controls and compatible retrofit solutions
Connected Hot Water Technology
THE BENEFITS OF SMART CONTROL
A Smarter Way to Manage Your Hot Water
Smart immersion heater technology can give compatible existing hot water systems many of the connected features associated with modern water heaters. Discover how greater control, intelligent scheduling and retrofit solutions can make everyday hot water management more convenient.
Intelligent Heating Schedules
Programme heating around your routine or use ECO functionality designed to adapt to regular hot water usage patterns.
Reduce Unnecessary Energy Use
Smarter scheduling and temperature management can help limit unnecessary heating, with potential savings depending on your usage and settings.
Upgrade, Don't Automatically Replace
Suitable existing installations may be upgraded using a compatible Wi-Fi thermostat or a complete smart immersion heater assembly.
THERMOWATT SMART RETROFIT SOLUTIONS
Choose Your Smart Heating Upgrade
Whether your existing immersion heater already uses compatible Thermowatt SMART technology or requires a complete replacement assembly, there may be a route to connected hot water control. Explore the two solutions below to understand the differences.
THERMOSTAT-ONLY UPGRADE
THERMOWATT TMEC3E WI-FI
TMEC3E Wi-Fi Thermostat Upgrade
Designed to replace the earlier TMEC-2 SMART thermostat on specified Thermowatt SMART immersion heaters, introducing Wi-Fi connectivity and MyThermowatt app control without replacing the existing compatible heating element.
- Wi-Fi connectivity and smartphone control
- Smart scheduling and ECO functionality
- Designed for specified existing Thermowatt SMART models
- UK aftermarket product code: 4303101
Compatible only with Thermowatt SMART immersion heater models: 3402106, 3402107, 000003402106, 000003402107, 3402029, 3402053, 3402060, 3402061 and 3402098.
COMPLETE IMMERSION HEATER
THERMOWATT WI-FI IMMERSION HEATER
Complete TMEC3E Wi-Fi Immersion Heater
A complete smart immersion heater assembly combining an Incoloy heating element with Thermowatt TMEC3E Wi-Fi thermostat technology.
Solutions are available for both 1¾-inch connections commonly used on unvented cylinders and 2¼-inch connections commonly used on vented cylinders.
The correct assembly must be selected to match the existing cylinder and installation requirements.
- Complete immersion heater assembly with Incoloy heating element
- TMEC3E Wi-Fi smart thermostat technology
- MyThermowatt app connectivity
- Smart scheduling and temperature management
- 1¾-inch and 2¼-inch connection options available
- Suitable for compatible vented and unvented cylinder applications
Available for compatible vented and unvented cylinder applications. The correct connection size, element specification and installation requirements must be verified before purchase. Specific UK product codes for the complete assemblies are to be confirmed.
MyThermowatt Connected Control
CONNECTED HOT WATER CONTROL
Smart Control at Your Fingertips
The MyThermowatt app brings connected hot water management to compatible TMEC3E Wi-Fi installations. Adjust settings, select operating modes and manage heating schedules from your smartphone.
Remote Wi-Fi Control
Access compatible hot water controls through the MyThermowatt smartphone app.
Heating Programmes
Set heating schedules to better suit your household's hot water routine.
ECO Mode
Use the dedicated ECO operating mode to support more considered hot water management.
Boost Function
Access the Boost function when you need to adjust your normal heating routine.
Holiday Mode
Select Holiday mode when your regular hot water requirements change.
Consumption Monitoring
View available consumption information to better understand your water heating usage.
MyThermowatt is available for iOS and Android. Thermowatt advises keeping the system permanently powered and connected to Wi-Fi for full functionality. If Wi-Fi is lost, the unit continues operating according to its last programmed settings.
COMPATIBILITY & INSTALLATION
Is Your Existing Water Heater Compatible?
Choosing the correct Thermowatt smart heating upgrade depends on the immersion heater already installed. A thermostat-only replacement is suitable for specified Thermowatt SMART models, while complete TMEC3E Wi-Fi immersion heater assemblies are available for compatible vented and unvented cylinders, including 1¾-inch and 2¼-inch connection options.
01
THERMOSTAT UPGRADE
TMEC3E Wi-Fi Thermostat Upgrade
The TMEC3E Wi-Fi thermostat is designed as an upgrade for the earlier TMEC-2 SMART thermostat fitted to specific Thermowatt SMART immersion heater models. It is not a universal replacement for conventional immersion heater thermostats.
COMPATIBLE THERMOWATT SMART MODELS
3402106
3402107
000003402106
000003402107
3402029
3402053
3402060
3402061
3402098
Thermowatt confirms that the thermostat-only upgrade is exclusively intended for the listed SMART immersion heater models. UK aftermarket reference: 4303101.
02
COMPLETE ASSEMBLY
Complete Wi-Fi Immersion Heater Assembly
The complete Thermowatt solution combines an Incoloy heating element with TMEC3E Wi-Fi thermostat technology.
Solutions are available for both 1¾-inch connections, commonly used on unvented cylinders and 2¼-inch connections, commonly used on vented cylinders.
The correct assembly must be selected to match the existing cylinder, element specification and installation requirements.
Connection size
1¾-inch and 2¼-inch
Heating element
Incoloy
Smart thermostat
TMEC3E Wi-Fi
Application
Compatible vented and unvented cylinders
TMEC3E Wi-Fi immersion heater assemblies are available for compatible vented and unvented cylinder applications. Confirm the correct connection size, element specification and installation requirements before selecting a replacement. Specific UK product codes for the complete assemblies are awaiting confirmation from Thermowatt.
BEFORE SELECTING A REPLACEMENT
What Should You Check?
Identify the Existing Immersion Heater
Check the manufacturer, model reference and current thermostat arrangement.
Confirm the Fitting Size
Establish whether the existing immersion heater uses a 1¾-inch or 2¼-inch connection.
Review Installation Requirements
Check electrical suitability, available space, safety controls and the manufacturer's installation instructions.
Use a Competent Installer
Replacement work should be carried out by a suitably qualified professional, following applicable electrical and hot water system requirements.
Not Sure Which Smart Upgrade You Need?
Contact Heatraq with your existing immersion heater model number and installation details. We can help you identify the relevant Thermowatt solution and clarify what information is needed to check suitability.
SEE SMART HEATING IN ACTION
Discover the Thermowatt TMEC3E Wi-Fi
See how Thermowatt's connected heating technology brings smartphone control and flexible hot water management to compatible immersion heater installations. Watch the manufacturer's official demonstration below.
Official Thermowatt product video, embedded with permission from the manufacturer. Product compatibility and installation requirements should always be checked before selecting an upgrade.
EXPLORE THE BIGGER PICTURE
Explore the Future of Smart Water Heating
Want to understand how connected water heaters, smart controls and intelligent scheduling fit together? Our Smart Water Heating Guide explains the technology, potential benefits and important considerations.
FREQUENTLY ASKED QUESTIONS
Smart Heating Controls: Your Questions Answered
Find answers to common questions about Thermowatt TMEC3E Wi-Fi technology, compatible immersion heaters, connectivity and installation.
Can I upgrade my existing immersion heater to Wi-Fi control?
Potentially, depending on your existing installation. Thermowatt offers two routes: a TMEC3E Wi-Fi thermostat upgrade for specified Thermowatt SMART immersion heater models, or a complete Wi-Fi immersion heater assembly for compatible installations.
Complete assemblies are available with 1¾-inch connections commonly used on unvented cylinders and 2¼-inch connections commonly used on vented cylinders. Compatibility must be checked before selecting either option.
Which immersion heaters are compatible with the TMEC3E Wi-Fi thermostat?
The TMEC3E Wi-Fi thermostat-only upgrade (UK reference 4303101) is designed for specified Thermowatt SMART immersion heater models fitted with the earlier TMEC-2 SMART thermostat.
It is not a universal replacement for conventional immersion heater thermostats. For other compatible installations, Thermowatt offers complete immersion heater assemblies incorporating TMEC3E Wi-Fi technology.
Check your existing immersion heater model before ordering.
Will my immersion heater continue working if Wi-Fi is lost?
Yes. Thermowatt confirms that the TMEC3E Wi-Fi continues operating according to its last programmed settings if the Wi-Fi connection is lost. For full smart functionality, Thermowatt recommends keeping the unit permanently powered and connected to Wi-Fi.
Does the TMEC3E Wi-Fi work with both 2.4 GHz and 5 GHz Wi-Fi networks?
Yes. The Thermowatt TMEC3E Wi-Fi features integrated dual-band Wi-Fi 6 connectivity, supporting both 2.4 GHz and 5 GHz wireless networks.
Unlike many smart heating devices that only support 2.4 GHz, TMEC3E Wi-Fi is designed to work more easily with modern dual-band home routers.
This can simplify initial pairing and reduce the need to change router settings or create a separate 2.4 GHz network, making installation and setup more straightforward for homeowners and installers.
Is the MyThermowatt app free to use?
Yes. Thermowatt states that the MyThermowatt app licence is provided free of charge to customers purchasing the TMEC3E Wi-Fi. The app is available for both iOS and Android through the Apple App Store and Google Play Store.
Can the complete TMEC3E Wi-Fi immersion heater be fitted to a vented cylinder?
Yes. Thermowatt has confirmed that complete TMEC3E Wi-Fi immersion heater solutions are available for both vented and unvented cylinder applications.
These include 2¼-inch connection options commonly used on vented cylinders and 1¾-inch options commonly used on unvented cylinders, with Incoloy heating elements.
The correct assembly must be selected according to the cylinder's connection size, element specification and installation requirements. Specific UK product codes for the complete assemblies are awaiting confirmation.
Does the TMEC3E Wi-Fi require professional installation?
Installation or replacement should be undertaken by a suitably qualified professional familiar with the relevant electrical and hot water system requirements. The installer should follow the manufacturer's instructions, verify compatibility and ensure the required safety controls remain effective.
YOUR NEXT STEP TOWARDS SMARTER HOT WATER
Ready to Make Your Hot Water Smarter?
Whether you're looking to add Wi-Fi control to a compatible existing immersion heater or considering a new smart electric water heater, Heatraq can help you explore the available options and make a more informed choice.
Thermowatt upgrade suitability depends on the existing installation. Contact us for guidance.