Tado is giving its tado° X heating system two new tricks: an AI-powered open-window detection that learns how each room normally behaves, and a mould index that rates damp risk room by room. Both features are rolling out in stages over the coming weeks through the tado° app, and both sit behind the company’s paid AI Assist subscription.
The update matters because it targets one of the most common sources of wasted heat in winter: radiators blasting away while a window stands open. It also turns the temperature and humidity sensors already built into tado° X hardware into an early-warning system for damp — a problem that is easy to miss until it becomes visible mould.
Open-window detection that learns your rooms
Tado has offered open-window detection for years. Until now, it worked by reacting to a sudden drop in temperature or humidity: if a room cooled quickly, the system assumed a window was open and paused the heating to save energy.
The new version replaces that single, one-size-fits-all model with an AI algorithm that learns what normal climate looks like in each individual room. That distinction matters, because rooms behave very differently. A bathroom after a hot shower, a kitchen during cooking, and a bedroom overnight all produce temperature and humidity swings that can look like an open window to a simple threshold-based detector — and trigger false pauses, or miss real ones.
By learning each room’s pattern, the AI is designed to tell a genuine open-window event apart from everyday activity such as cooking or showering. When the app suspects a window is open, heating pauses temporarily for that room, then resumes its normal schedule once the event is over.
The app shows, per room, whether the feature is still learning or has finished learning, so owners can see when detection is fully tuned. Each room needs its own measuring device — a tado° Smart Radiator Thermostat or a Smart Thermostat that records both temperature and humidity — for the feature to work there.
Tado has not published accuracy figures for the new detection, so how much better it performs than the old version in real homes remains to be seen once it reaches users.
A mould index for every room
The second new feature is a mould index, shown per room inside the app’s Air Comfort section. Every room is rated low, moderate, or high, giving owners a simple read on damp risk without having to interpret raw humidity graphs.
The index uses the VTT growth model, a Finnish model that estimates mould growth from temperature and humidity measured over a longer period, rather than reacting to a single damp day. That longer view is the point: mould risk builds up over weeks of cool, humid conditions, not from one steamy shower.
The feature is most useful in winter, when homes are ventilated less and damp-prone rooms such as bathrooms and bedrooms are more at risk. As with open-window detection, a room needs its own sensor point — for example, a Smart Radiator Thermostat X — to get its own rating.
What else is changing in the app
Not everything in this update is behind the paywall. The tado° app’s home screen is now customisable for all users: tiles can be moved, hidden, and restored later, so owners can put the controls they use most at the top.
Heating Boost also now appears as a Live Activity on iPhone, including the Dynamic Island, as well as on Apple Watch and Mac. That addition is free for tado° X users, making it easier to see and manage a temporary heating boost without opening the app.
Price, availability, and the V3+ question
Open-window detection and the mould index are part of AI Assist, which costs €3.99 per month or €29.99 per year. The subscription also includes geofencing, holiday mode, preheating before you arrive, and adaptive heating, which learns how each room heats up and cools down.
Importantly, tado describes the new open-window detection and mould index for the tado° X system only. If you still run the older V3+ generation, the announcement does not mention it, so owners should assume these features may not arrive on that hardware.
The staged rollout means not every tado° X owner will see the features on day one; they are arriving over the coming weeks via an app update.
Why this update is worth watching
The update lands shortly after tado refreshed its flagship hardware with the second-generation Smart Thermostat X, a 17.8 mm-thin wall unit with a circular touch interface, a USB-C rechargeable battery rated for more than a year, and Matter and Thread support. The hardware refresh and this software update point in the same direction: the thermostat is becoming less of a wall dial and more of a sensing and software platform.
That shift is visible across the smart home industry. Basic scheduling and remote control are now table stakes, and manufacturers are differentiating with learned behaviour, per-room intelligence, and health-of-home features — increasingly delivered as subscriptions. Tado’s mould index is a good example: it repackages sensor data owners already generate into a plain-language risk rating.
The open question is value. At €29.99 a year, AI Assist only makes sense for owners who will actually use several of its features — geofencing, adaptive heating, and now open-window detection and the mould index together. For tado° X owners, the new features are a reason to look at the subscription again. For V3+ owners, they are a reason to weigh an upgrade — or to wait and see whether tado extends the features to older hardware.
Either way, if you run a tado° X system, check the app over the coming weeks: the learning status for each room will tell you when the smarter detection is ready, and the Air Comfort section will show whether any room deserves a closer look before winter damp sets in.