Tado app gets "Heating to" temp wrong and keeps overheating the house
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I've got a simple Python script going that scapes the downstairs thermostat data every minute.
A few details that I found interesting.
The 'Heating Demand' that is shown with the 3 bars in the app actually has a lot more finer grained control in the back-end. I've seen 8%, 40% etc.. It's not just 0, 33, 66 and 100.
The inside temperature reading of the thermostat only updates every 15 minutes or so. It lists the timestamp of the last reading. This seems quite slow.
The aim of the script is to capture moments when the algorithm is going wrong for more ammo to give to support.
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Anyone noticed any improvement lately?
I've not noticed any serious overshoots since they reset my configuration.
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Nothing more than a degree over, usually when the weather changes.0
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This is what mine looks like today. Pretty consistent. Rises at the end when I turned it up a degree.
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Late reply but this is the first thread that shows up in a web search.
I have recently had the same problem and the explanation from tado is disingenious.
Same usage pattern as 'Karmageddon 16th Feb 2021 03:51' - First thing I did was delete all the time blocks and for 1.5 years I used manual control for individual rooms. In Nov '23 I set my first schedule time blocks for 18 degrees day and 16 night. It worked okay for a week or two, then suddenly started heating the room to 18.3, 18.5 and so on (immediately as I modified the schedule once it was already active). At that EXACT time the app started displaying 'Inside now 18.3' but continued to say 'Heating to 18 degrees'. I am CONVINCED it's a software bug because it only displays the 'Heating to' message for 1 out of 8 rooms, and only from the exact time I made a second change to the schedule for that room.
(I do have another small room that's set to 12 and overheats to almost 15, but that's becuse the radiator is massively oversized, apparently tado is so smart that it can't figure out that shutting the heat off earlier would let the room continue to warm up from resudual rad heat. So smart.)
The issue is not continual heating either, but it would get to 18.3, the CH light on the receiver turns off, the relay clicks off, the boiler turns off. But then a minute later WHILE ALL ROOMS ARE ALREADY WELL PAST THEIR SET POINTS, the CH light comes on, the relay clicks on and the boiler starts up again. So it's not even incidentally heating past the set point because their algorithm can't profile a room and calculate how to switch off early leaving the residual heat to finish the job. It's switching off just after the set point, then for some reason it's literally making a decision to turn the heating back on again even though all rooms are already warm.
My DAILY gas consumption for December went from £3/day to nearly £7/day just from letting them control the schedule.
So I contacted tado and got to this reply last week:
""
Hello,
Thank you for the information-
According to our data, it seems that the Smart Radiator Thermostat works correctly.
The tado° Smart Thermostat is a PID controlled thermostat. This means that tado° not only looks at the current temperature but also at the overall temperature trend.
In other words, it will turn the heating on until the room temperature increases just above the set-point. Then the heating will remain off until the temperature starts to drop.
In doing this, tado° can prevent your heating from switching on and off too frequently and thereby protect the boiler from excessive wear and tear. It is also much more efficient in terms of energy usage.
It can also happen that, when tado° notices the temperature is dropping very quickly, it will start to heat in order to prevent the temperature from dropping too far below the set-point, even though the current temperature is above the set-point.
""
But that's exactly what it is doing: switching the heating on and off repeatedly, subjecting my boiler to excessive wear and tear, just at a temperature that they choose which is higher than the temperature I asked them for.
So basically I have smart heating that's less smart than the dumb heating it replaced. Simple fact: If I leave their algorithm to control it then I get huge bills. I also tried manual control with set temperatures, but even that still overheats the room then continues turning the boiler on and off, while displaying 'Heating to' FOR ONE ROOM ONLY. So the only option is to use basic manual control where I have to constantly monitor the app with my eyes then manually switch off when I'm warm enough. At least my old thermostat could be set to 18, then indefinitely heat to 18, cool down to 17.5, heat to 18. Apparently tado is incapable of replicating this lmao.
Yet they act like nothing on their side could ever possibly be a bug, it's always something you're doing - signal, positioning, batteries, even getting a plumber in to move radiators around so the TRV is closer to the bridge comes into their heads before the thought 'these guys might find a wireless repeater useful'. No, they supply the bridge with a 30cm cable then tell you that to get a good signal, be prepared to hang it in the middle of the room off a light shade like some kind of modern art ornament.
On one hand they have a 'energy guarantee' where they will accept a return if you can prove your energy bills are more expensive.
On the other hand they keep repeatedly turning the boiler on and off when the room is already well past the temperature, under the guise of 'some kind of predictive heating' and 'protecting the boiler'. But their system cycles the boiler anyway, and heats to a higher temp, then keeps burning gas. And anyone who has watched a government ad for 'turning it down by one degree saves money' (or anyone who saw my bill for December) would instantly notice that there's no way heating to 18.5+ is ever going to be cheaper than heating to 18, or that repeatedly cycling the boiler is an acceptable thing to do.
I tried the energy guarantee route and they simply ignored the requests, as well as any questions I asked about warranty, eventually being told if I am not happy with tado then I should remove it and sell it (even though I was still in warranty, and reporting a faulty product). So I was stuck with it, the only alternative being to travel to Germany to sue them, because of course they have that clause in their T&C that any legal action will take place in their country. To me that just indicates that many of us have gone down the same route so tado already know how to deal with us.
Personally I think their business model is 'sell hardware then fob people off til they get frustrated and replace it.' Because their heating doesn't work properly, but let's face it they will never fix it or even admit it. Notice how their only option to get 'support' is a featureless chat box that feels like trying to shout through a tiny hole in a wall? That's by design.
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I do find overshoots less of an issue if you lower your flow temperature. It's almost like Tado has been tested on low flow temp systems and doesn't respond quick enough if you turn it up.
This kind of interacts with the thermostats only updating every 15 minutes. I suspect they did this to try and smooth out their system. Their algorithm to me just seems badly implemented.
Like you say, a dumb thermostat seems to regulate better than Tado a lot of the time.
I wish heating controller companies would open source their software so issues like this could be fixed. I hate this closed software mentality, that they know best. They clearly don't given the number of issues like this people have.
Had the algorithm been open source, bugs like this would have been fixed years ago.
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Nobody from tado looks at these forums anymore, so this will not get fixed0
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I agree. Soon as I can afford to, I'm selling it to some other poor mug and putting my old timer back in, then just run around the house adjusting TRVs as needed. It's far, far cheaper to run. And I think they know that, that's why they ignore any support questions I ask about why my tado uses more than 2x as much gas.
Or look for an open source version. But I'm tired of having to invest hundreds of £££'s in something just to find out it's unconfigurable and doesn't work properly.
Their 'tado is working properly' responses are frustrating. I think it's intentionally designed that way. Their extremely limited chat support system seems to support that, with no ability to view or export previous conversations - it's intentionally encrappified, designed to cause frustration through obfuscation and confusion, designed to make us get frustrated and give up.
They don't care, they already made the sale.
At this point I just hope some poor potential future customers have the foresight to read these posts before deciding to invest in this rubbish.
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I'm having the same issue - so is there no solution to this?
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@RodneyRabbit I have the same behaviour from my thermostats as you do, it without fail heats to 1c above set point when it has a bigger heat demand to fill. And then I also had the problem of it short cycling AFTER it had already exceeded the temperature by 1c 😂 The one degree over thing I suspect is something to do with it being more efficient to keep heating a bit more after it's already heated a lot. The short cycling is just illogical nonsense and unfortunately Tado seems to have a lot of illogical behaviour. I've been trying to work with support for months to get it working in a somewhat reasonable way, progress has been slow and not particularly successful which prompted my suggestion for releasing the configuration parameters to users. Something that I suspect will never be implemented and will join the graveyard of other much needed suggestions that never went anywhere for years 🤷♂️
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I've only read the 2024 replies, but it sounds like there could be a couple of problems for you guys, which I've overcome by tweaking my system config and boiler. There are a bunch of factors to consider, but to keep things simple I'll just go through my solutions, which may or may not apply.
- My boiler is far too powerful, with output power of 9-24 kW. The house only needs 5 kW on the coldest day (in the last seven years of keeping records). Today, with 1C outside, the house needs around 3 kW. It is impossible to keep the boiler running without overheating the house. There has to be some cycling. One solution I've applied is to range rate my boiler output down to the minimum of 9 kW. It's nowhere near enough, but it's a start.
- By default Tado seems to have a minimum firing time of 3-4 minutes. It can go longer if necessary but not less. However, because I've range rate my boiler to 9 kW, a firing cycle of 3:40" to be precise does not put anywhere near enough energy into the system to be worthwhile. Therefore I requested Tado to increase the minimum firing time to 10 minutes. This is far more effective and helps reduce short cycling.
- If all SRTs are left connected to the zone controller then each one can force the boiler to fire. There is no way to synchronise the calls for heat, so you can have a situation where they take it in turns to fire up the boiler for a short time. My solution is to make seven of my eight SRTs independent. These SRTs cannot force the boiler to turn on, but must wait for heat when the one remaining SRT does fire the boiler. This synchronises the heat demand, so that most, if not all radiators are ready for business when the boiler is running.
- I've tried to use e-Bus connection to my Vaillant combi twice in the past three years, but each time I've been forced to return to relay switching. The reason is, as with the first point, boiler power. It cannot modulate output low enough to maintain the low flow temps requested by Tado. It shoots straight past them far too quickly and immediately shuts off, only to repeat five minutes later, over and over.
- We do not micro-zone the heating between rooms. None are turned off. All are set to between 18-19C day and night, with the lounge allowed, not forced, to reach 20C. In this way the whole house heats and cools as one. It's almost like having one big radiator distributed throughout the house rather than nine individual ones all doing their own thing.
The only room in my config that can turn the boiler on is the coldest room in the house - the kitchen. If I set this to a "comfortable" temperature then the remaining rooms should also be comfortable. That's the theory and it works well enough in practice. This does assume correctly sized radiators and a well balanced system.
Anyway, my heating is on 24x7 through the winter months. Here is the temperature graph for the kitchen so far today....
The temperature target of 18C has been maintained within +/- 0.2C.
And here is the lounge, set to 19C overnight and holding that temp also within +/- 0.2C.
Note that at 07:00 the lounge is set to 20C, but the temperature has not climbed at all. 20C is a temperature LIMIT rather than a temperature TARGET. It is allowed to keep heating as high as 20C, but it will not force the boiler to fire in order to achieve it. It can only take heat when the kitchen needs heat.
If 20C was required then, either I could boost the kitchen temp by a degree or so, or I could link the lounge back to the zone controller so that it can also force the boiler to fire. Note that we have no doors between kitchen, hall and lounge, so temperatures are somewhat linked between them. If one room gets too cold then it creates cold drafts at floor level - no good for the tooties in the living room. This is why heating the kitchen is as important as heating the lounge.
And another point of system refinement - the kitchen SRT is sitting loose on top of the valve. It cannot close off that radiator. It is a secondary bypass radiator, in addition to the hall. And that's also true of the landing - with the SRT sitting loose and acting as another bypass radiator. This means that there is always a minimum of three radiators open at any time, distributing heat to the coldest room and the core of the upstairs and downstairs. Again this is all to help limit cold drafts and it means we are comfortable at lower overall room temps throughout the house than might otherwise the the case.
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