The older face is the better-value option
The first Wired Smart Thermostat X is still a sensible purchase beside its redesigned successor. On September 10, 2026, Tado listed it at €89.99 in Germany and £79.99 in the UK. The second generation was €119.99 or £109.99. Saving €30 or £30 does not mean giving up the Tado X heating platform or direct Matter control.
What you give up is the newer physical interface. RU04 has a backlit LCD, three mechanical buttons and three replaceable AAA batteries. That is a reasonable combination for a thermostat mostly left to follow its schedule. Fresh batteries are an easy swap, and a button is familiar to visitors. The new light ring is more visually interesting, but a neglected hallway thermostat does not need to be a design feature.
Its value grows with the rest of the heating system
Replacing an awkward programmer with app schedules and remote control can be useful on its own. Tado's stronger argument is a house with different needs in different rooms. Add suitable Tado radiator valves and those rooms can request heat from the controlled system; a remote Tado sensor can give a room a better measuring point.
Those are extra purchases, not abilities supplied by the wall thermostat alone. Nor does a central thermostat create independently heated rooms without the appropriate valves or existing zones. If the existing controller already gives the house a comfortable routine, keep it until there is a specific inconvenience to fix.
The wiring also fixes the location of this model. Its compatibility with selected relay and OpenTherm systems, including water-based underfloor heating, is useful only when the actual equipment and connection match. If the useful measuring spot is across the room and there are no wires there, the wireless kit deserves the comparison.
Free schedules, paid automation
The free app provides temperature control and schedules stored on the device. The schedule can continue if the internet connection fails. AI Assist adds automatic away control, arrival preheating and other advanced features, with a current European price of €3.99 monthly or €29.99 annually. Some functions depend on the heating hardware: adaptive valve control needs radiator thermostats, for example.
Matter lets family members use their preferred supported home app for thermostat commands. It does not reproduce the whole Tado service or expose domestic hot-water control. A compatible Thread border router is required; you may already have one, otherwise a starter kit or separate Bridge X adds to the cost.
Tado's app connection also matters for firmware updates. Its current Alexa guidance warns that an Amazon Thread router used alone may not provide that connection. Price the complete working system rather than assuming the presence of an Echo makes every extra unnecessary.
Keep the right older hardware
RU04 works with newer Tado X products, so choosing it does not strand you on a separate first-generation network. V3+ is different: X cannot join the same Tado Home, and X supports fewer modulating boiler protocols. A functioning V3+ system using a non-OpenTherm control method is a particularly weak candidate for a casual replacement.
Buy RU04 for a supported wired installation when the saving matters more than the light ring and rechargeable battery. Choose the newer model when the controller is visible and used daily. Neither needs to replace a working thermostat merely because it can.
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