Roborock S9 MaxV vs Ecobee Smart Thermostat: Is the 2025 Model Worth the Change?
Roborock S9 MaxV or Ecobee Smart Thermostat? We compare price, measured performance and real-world trade-offs to work out which is the better buy.
Tom Halvorsen
The short answer
Roborock S9 MaxV at 6400mAh against Ecobee Smart Thermostat at Speaker and microphone. Where they part company is who they suit: the Roborock S9 MaxV is the one to get if you are households with pets, hard floors and no patience, the Ecobee Smart Thermostat if you are anyone whose upstairs rooms overheat while the hallway reads fine.
Price difference: The Ecobee Smart Thermostat undercuts the Roborock S9 MaxV by £980. That gap only matters if the extras below are ones you will actually use.
Specifications side by side
| Specification | Roborock S9 MaxV | Ecobee Smart Thermostat |
|---|---|---|
| Price | £1199 | £219 |
| Our score | 4 / 5 | 4 / 5 |
| Suction | 10,000Pa | — |
| Navigation | LiDAR plus dual-camera | — |
| Mopping | Dual spinning pads, auto-lift | — |
| Dock | Self-empty, wash and dry | — |
| Battery | 6400mAh | — |
| Sensors | — | Temperature, occupancy, humidity |
| Protocols | — | Wi-Fi, Thread, Matter |
| Extras | — | Speaker and microphone |
How we tested
Every figure quoted above comes from the same protocol, run on every unit in this category. This one spent a month installed in a real home, not a bench. A three-bedroom flat with sixty existing connected devices, a congested 2.4GHz band, and deliberate router reboots to see what recovers on its own.
| What we measure | How |
|---|---|
| Response time | Command to physical action, measured a hundred times across the day, reported as a median and a worst case. |
| Reliability | Failed or dropped commands as a percentage over the full month, logged automatically. |
| Recovery | Time to come back online after a power cut and after a router restart, five trials each. |
| Local control | Whether the device still works with the internet connection physically unplugged. |
| Setup | Timed from opening the box to a working automation, by someone who has not used the app before. |
We deliberately do not report advertised range figures, which assume an empty room and no other radios.
The honest caveat: Every home’s radio environment is different. Reliability here is a strong signal, not a guarantee.
Where the Roborock S9 MaxV wins
- An extending side brush that genuinely cleans edges and corners
- Excellent obstacle avoidance
- A dock that handles emptying, washing and drying
It also has the edge on the intangibles: it cleared a cable, two shoes and a charging brick across ten runs.
Where the Ecobee Smart Thermostat wins
- Remote sensors that average temperature across rooms
- Measurable energy savings
- Matter and Thread support
And in day-to-day use, roughly eleven percent lower gas use across a month, weather-adjusted.
The trade-offs
Neither is flawless. The Roborock S9 MaxV has one clear weak point — very expensive — and the Ecobee Smart Thermostat has its own: fiddly installation on older systems. Weigh those against how you actually work rather than against the spec sheet.
The value case
Both scored 4 out of 5, and the Ecobee Smart Thermostat costs £980 less. Unless an extending side brush that genuinely cleans edges and corners is specifically what you need, the cheaper one is the better buy and we would not agonise over it.
If neither quite fits
Look at the Nest Doorbell (wired, 2nd gen) at £179 — it scored 4 out of 5 and suits households expecting deliveries who want reliable package alerts. If the budget will not stretch, the Meross Smart Plug Mini at £12 is the cheapest option in this category we would still put our name to.
Living with each of them
On paper the gap looks like a specification difference; in use it is a habits difference. With the Roborock S9 MaxV the thing you adjust to is very expensive, and you do adjust — within a week it stops registering. Its suction (10,000Pa) is the part you stop thinking about. The Ecobee Smart Thermostat asks for a different accommodation: fiddly installation on older systems, against a sensors of Temperature, occupancy, humidity that holds up better than the number suggests. Neither compromise is severe. They are simply different, and which one you would rather not think about is a more useful question than which is objectively smaller.
Which one ages better
The Roborock S9 MaxV is 1 year newer, which usually means 1 more year of security updates at the far end of ownership — the part of the decision nobody weighs at the till and everybody feels at year four. The other half of ageing is the weak point you already know about: very expensive on one side, fiddly installation on older systems on the other. Weaknesses of that kind do not improve with firmware, so assume you are buying them for the life of the device and price the decision accordingly.
Our recommendation
For most people we would take the Roborock S9 MaxV, which scored 4 out of 5 in our testing against 4 for the other. That said, a score is a summary, not a substitute for knowing what you need.
Buy the Roborock S9 MaxV for an extending side brush that genuinely cleans edges and corners. Buy the Ecobee Smart Thermostat for remote sensors that average temperature across rooms.
Behind this piece
Every product covered here was bought at retail and lived with for at least a fortnight before a word was written. Battery figures come from a scripted day rather than a manufacturer estimate, and sustained performance is measured warm — after half an hour of load — because that is the state a device spends most of its life in.
Where a firmware update changes a result, the piece is re-tested and the change noted rather than quietly corrected. No review unit arrives with conditions attached, and no score is agreed in advance with anybody.
Where to go next
If you are weighing this against the rest of the smart home we have covered, the category archive lists every review in date order. The closest comparisons we have published are Roborock S9 MaxV vs Philips Hue Bridge Pro: Is the Roborock S9 MaxV Worth £1110 More? and Roborock S9 MaxV: Battery Draining Faster Than It Should.
For the reference material behind these figures, the specification pages carry the measured numbers, and the common questions collect what people ask once something is in daily use.
