A worthwhile redesign where you will actually use it
The second-generation Wired Smart Thermostat X is easier to want than a plain thermostat with three buttons. A circular touch control and light ring handle temperature changes, while a top button can resume the schedule, boost heating or show humidity. Those are useful physical shortcuts for the person standing in front of it, without reaching for a phone.
The matte-white body is thinner at 17.8 mm, but it occupies more wall space: 110 × 110 mm versus the first generation's 100 × 100 mm. “Slimmer” does not mean smaller in every direction. Its LED matrix and illuminated ring give it a more deliberate appearance, which matters most in a frequently used room.
That is the case for paying more. It is much weaker if the thermostat sits in a hallway and is rarely touched. A new face does not by itself make the heating more efficient.
Rechargeable is convenient, with a different chore
RU05 replaces the earlier model's three AAA cells with an integrated USB-C rechargeable battery. Tado describes a charge as lasting through the heating season; that remains a manufacturer claim rather than a runtime tested here. A cable is not included.
Avoiding disposable batteries is welcome, though you now need to remember charging instead of keeping spare AAAs. Tado's current support guidance also notes that some fast chargers may fail to charge its rechargeable devices and recommends a basic USB-A supply with a USB-C cable as a fallback. This is a small ownership detail worth knowing before assuming any nearby laptop charger will do.
The extra €30 buys hardware
On September 10, 2026, RU05 cost €119.99 in Germany or £109.99 in the UK. The first-generation RU04 was €89.99 or £79.99. Both use the same Tado X platform and can work alongside the same X radiator valves, remote sensors and receivers.
The free app includes schedules stored on the thermostat and remote temperature control. AI Assist is separate, currently €3.99 monthly or €29.99 annually in Europe. Buying the newest thermostat does not include automatic away handling, arrival preheating or the service's other paid features. Those features also depend on the relevant room and heating hardware.
If you need a Thread connection, the second-generation starter kit adds Bridge X at €179.99 or £159.99. A compatible existing border router can make that kit unnecessary. The complete cost should also allow for any installation work and remote sensor needed to represent the room properly.
A better controller still needs the right job
This model replaces a supported wired room thermostat or controls a compatible water-based underfloor heating zone. Relay and OpenTherm support do not cover every boiler protocol. A wireless kit is the relevant alternative when a receiver should sit by the boiler and the room controller elsewhere.
Matter shares ordinary thermostat control with supported home apps; Tado retains its heating-specific features and firmware management. Domestic hot-water control is currently outside Matter. Home Assistant users need its Matter integration: the separate legacy Tado integration does not support X.
Keep a working first-generation X thermostat unless its buttons or battery arrangement bother you. Keep a good V3+ installation unless replacing the wider system makes sense: it cannot share a Tado Home with X, and some older boiler-control protocols are absent. RU05 is a good hardware upgrade for a new installation, not a compulsory upgrade for existing owners.
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