Smart radiator thermostats inaccurate temperature

BenB · ‎2022-12-14

I know that the radiator valves use an algorithm to estimate the room temperature. Being so close to the heat source, it's impossible for them to accurately measure the room temperature themselves.

But some of them seem to be way out.

The one in my kitchen was reporting 24, which I could tell was way higher than reality, so I reallocated the room thermostat to the kitchen and moved it, and it reported 18. Others don't seem to be as wildly out as that.

It would be good if Schneider sold room thermostats without a screen, cheaper than the existing room stat, so that we could get an accurate room reading. Or allow you to take the room stat into each room to take a single reading, and use that to correct and improve the rad stat accuracy.

My question is, will the algorithm improve over time, or am I stuck with having to set the setpoint temperature 5 or 6 degrees higher than the temp I actually want?

PhilHornby · ‎2022-12-14

@BenB wrote:
But some of them seem to be way out.

Given a choice, you'd never put a temperature sensor next to a radiator, or - when the heating's off - next to a cold wall. The algorithm to make some sense of it, must be quite involved.

As my system grew, I decided it needed Roomstats in important rooms, but I would live with the iTRVs as sensors in others.

Here is some data from my two Lounge iTRVs (red and green) vs the temperature as seen by the Roomstat (blue). Not only is there a discrepancy, but it's not by a fixed amount.

@BenB also wrote:
It would be good if Schneider sold room thermostats without a screen, cheaper than the existing room stat, so that we could get an accurate room reading.

I'd second that - the existing products are extortionately expensive, especially if you want them in a trendy 'primer' colour! (anthracite?)

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3 Channel Hubᴿ, 13xiTRVs, 8xRoomstats and 2xSmartplug/Repeaters. (UK)

BenB · ‎2022-12-14

In the absence of linked room stats that are more affordable, there ought to be a way of the user inputting an accurate room temperature into the app (whether they took that reading with a normal thermometer or by walking round the house with the room stat) so that the algorithm can get better data and therefore be more accurate.

One for Schneider to ponder for a future update hopefully.

In the meantime I'll just set my rooms to have a target temp of 4-6 higher than I really want.

SamJ · ‎2022-12-15

Yes I've had to do the very same this morning - my kitchen TRV thinks it's 3c warmer than it actually is (tested using several other thermometers in the room) - so I've had to raise the temps on the kitchen schedules.

Other TRVs seem fine, but I agree with your suggestion of Wiser selling cheaper room thermostats for the main purpose of getting accurate readings. It would be good to have the option of buying one of these for areas where the hardware and/or algorithm is struggling.

SAtewart · ‎2022-12-15

Schneider have made a world product that works well and invisibly to the majority of users. I personally think the pricing is good when its saving me £150 to £200/ winter month. Us enthusiasts maybe should live with the limitation. The graph shows that you probably need to populate your schedules with doctored temperature set points to achieve what you are after.

However I have seen in commercial energy management systems the ability to enter an offset which forces the reported readings closer to actual measured mid room height values. The graph above does however show that the variation is not linear - but is that really a material consideration? The deviation is small and in real life there are a number of variables that could be affecting a measured value.

SamJ · ‎2022-12-15

Agree to a point, but I'd hope that the the Wiser team see the enthusiasts here as wanting to help and improve what is, as you say, already a very good product. Whilst I'm happy to live with the limitations, as I expect Wiser don't have limitless resources(!), I think it's good that issues are flagged so that they can review and ultimately dedicate the resource they do have into improving the product where required.

SAtewart · ‎2022-12-15

I think that continuous development is the thing that any company serious in getting and keeping market share must invest in. The app, I think, needs to get better (functionally and non-functionally) or people (who are used to changing £hundreds phones every three years) will migrate.

While I am happy to tinker and investigate "design features", my wife and even my post grad son are put completely off using the rich functionality because the app does not accurately reflect user input and system status.

I hope the Schneider support crew value and are making use of all the free user acceptance and user experience testing we are giving them for free.

BenB · ‎2022-12-15

@SAtewart wrote:
Schneider have made a world product that works well and invisibly to the majority of users. I personally think the pricing is good when its saving me £150 to £200/ winter month. Us enthusiasts maybe should live with the limitation. The graph shows that you probably need to populate your schedules with doctored temperature set points to achieve what you are after.

However I have seen in commercial energy management systems the ability to enter an offset which forces the reported readings closer to actual measured mid room height values. The graph above does however show that the variation is not linear - but is that really a material consideration? The deviation is small and in real life there are a number of variables that could be affecting a measured value.

Totally agree that the product as a whole is excellent. Easy to install DIY (although I still haven't got round to removing the old wired room stat!), very easy to set up, and the network so far has been solid. Good VFM compared to the other options (most of which are not as good)

But we would still like it to be better, and pointing out areas for improvement are going to benefit Schneider as well.

david101 · ‎2022-12-22

Had an email from SE tech support today stating that new TRV firmware is being rolled out in the next 24hrs, Im hoping to fix the temperature issues and maybe make the TRV a bit quieter.

david101 · ‎2022-12-23

No new firmware deployed on my TRV's today so I dont know why the techie said there was new firmware coming.

Lebesgue21 · 1 week ago

@BenB wrote:

It would be good if Schneider sold room thermostats without a screen

Actually they already sell a temperature (and humidity) sensor that should do the job (CCT593012), but for a reason I don't understand Wiser still prefer to use the unreliable temperature from the smart radiator thermostat as an input instead of the one measured by the temperature sensor.

I just created a feature request, hope it'll be taken into account: https://community.se.com/t5/Schneider-Electric-Wiser-Forum/Feature-request-use-room-thermometer-as-m...