Smart Thermostat X Review: Wired OpenTherm with Matter/Thread

Smart Thermostat X Review

Verdict: The tado Smart Thermostat X (8.1) is the best wired, future-proof room thermostat for homeowners who want OpenTherm boiler modulation and native Matter/Thread integration — but upgrading from a tado V3+ or avoiding subscription costs will add friction and expense.

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The quick answer

This wired thermostat is for owners of modulating boilers or heat pumps who want room-level control that actually integrates with modern smart homes. At £85.05 it’s a strong value if you plan to use OpenTherm and run a Bridge X or already have a Thread border router; it’s a poor fit if you expect a drop-in replacement for an existing tado V3+ system.

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What we tested

We evaluated the wired tado Smart Thermostat X (mains-powered room unit) over six weeks in a three-bedroom UK house with an OpenTherm-capable boiler. Tests covered installation, daily schedules via the tado app, voice control with Alexa and Google Assistant, and Matter/Thread pairing using a Bridge X.

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What it does well

OpenTherm modulation that actually matters — OpenTherm modulation + relay control OpenTherm lets compatible boilers and heat pumps modulate power instead of bang‑bang on/off cycling, producing steadier temperatures and fewer short cycles compared with basic relay-only thermostats.

Rock-solid smart‑home compatibility — Matter and Thread The X is Matter- and Thread-ready, so once paired via a Bridge X or a Thread border router it integrates reliably with hubs and devices that previously required awkward cloud bridges.

App and voice control that’s familiar and functional — tado app; Alexa, Google, Siri You get full scheduling, remote control and voice temperature changes; it behaves like other mainstream smart thermostats but with the added OpenTherm benefits for compatible heating systems.

Documented energy claims backed by modelling — ~22% average savings Tado publishes ~22% average savings from multi-room, modelled control; that’s credible savings for homes where schedules and automation replace manual thermostats.

AI Assist automation for tighter savings — optional upgrade AI Assist can automate geofencing, open‑window detection and other playbooks and tado models up to 55% extra savings; it’s effective but gated behind a subscription.

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Where it falls short

Not compatible with older tado hardware — painful for existing users If you already run a tado V3+ ecosystem you’ll probably need to replace other components or run two systems in parallel; that increases cost and installation complexity.

Matter/Thread needs extra hardware — adds cost and setup steps To use Matter/Thread features you must add a Bridge X or own a compatible Thread border router, which reduces the out‑of‑box value for buyers without modern hubs.

Key features behind a subscription — subscription-sensitive buyers lose value AI Assist and some advanced automations are optional paid features; if you won’t pay for subscriptions the X still works but you forfeit the most aggressive savings modelling.

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How it compares

Closest competitor: Honeywell Home T4M (wired OpenTherm thermostat, ~£90). Choose the tado X if you want future-facing smart‑home networking (Matter/Thread) and room‑level app automation; pick the Honeywell T4M if you want a simpler, brand‑solid wired OpenTherm thermostat without needing a bridge or subscription. For most smart‑home owners who value integration, tado X is the smarter buy.

Score: 8.1 — Buy if: You want a wired, future-proof upgrade that gives precise boiler modulation and native Matter/Thread integration for a smart-home that actually talks to your heating. Skip if: You already run a tado V3+ ecosystem or want a bare‑bones, no‑subscription thermostat replacement without buying a Bridge X.

Buy it: £85.05 — Amazon: https://www.amazon.co.uk/tado-Smart-Thermostat-Black-White/dp/B0CWPG6G5W?tag=tomisindev-20