Energy consumption with Tado
I updated my old wired thermostat and programmer with Tado Smart V3+ wireless system (including smart radiator valves). I set individual temperatures in every rooms and I realized that my boiler is on much frequently but for shorter periods than before, according to the heat demand per rooms. Obviously trying to keep the overall temperature/comfort in my house as before. Let me add that before TADO I adjusted the old dumb TRVs daily to save gas by not heating rooms are not in use all day/night. After using TADO for a month now, my experience is that my gas consumption is much higher than it was with the old system. I have an old system boiler (Potterton Suprima 50L) with hot water cylinder. Is it possible that as my old bolier is heating up more times as before and the heating up cycles are using more gas? Is it possible that I cannot save any energy/gas with my Tado system thanks to the old boiler? Please advise. Thanks
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The short answer is that, for me at least, Tado has contributed to genuine savings on energy consumption. I installed it myself, a little over three years ago. In the same year I did also upgrade all windows and external doors, so Tado cannot take all the credit, but 2024 has seen my lowest energy usage in the past seven years for which I have detailed data.
However, it's been a learning curve to work out the best way to use Tado, and I certainly don't use it with "out of the box" settings. I have nine rooms, the hall with a smart wired thermostat and eight rooms with Tado SRTs. My system is configured so that only the kitchen can call for the boiler to turn on. It is the coldest room in the house and there are no doors between the kitchen, hall and lounge. Therefore there is the potential for cold drafts from the kitchen reducing comfort on the lounge. Thus I make sure the kitchen is "warm enough".
For all the other rooms I've set the SRTs to "Independent", meaning that they cannot make the boiler fire. They have their own schedules, but must wait for the kitchen to fire the boiler before they can begin heating.
This avoids the situation you've found, where individual rooms keep firing the boiler on turn for short periods. Effectively I am heating the whole house as one unit instead of nine individual rooms. All rooms are set to similar temperatures. None are turned off or turned down.
The rooms are set to the desired temperature, which effectively becomes the upper limit for those rooms rather than the target. i.e. the SRTs are open much of the time, waiting for the kitchen to fire the boiler and they will only close in order to avoid overheating each room.
All of this improves boiler efficiency and does not compromise comfort.
It's also worth noting that the house is usually occupied 24x7 and the heating is always on, controlled purely by thermostat.
I've also made changes to the boiler settings, reducing the CH output to the minimum possible and limiting the flow temperature to 50C. Once again this aids boiler efficiency. It works well with our 24x7 heating regime, but might be less suited to the needs of a working family who only need a boost in the morning and evening.
Unfortunately, there is no one size fits all. Each household will have their own specific needs, with their own schedules for occupancy and considerations to be made regarding the insulation levels and heat loss performance. Then you've got radiator size to consider - can they be run effectively at lower floor temperatures? What are the characteristics of the boiler? Etc. Etc. Like I said, I've had Tado for over three years and I'm still making occasional tweaks to setup in the pursuit of highest comfort at lowest cost.0 -
Thanks for your detailed answer. How can you set SRTs as independent not to make the boiler fire? It was also not clear for me what is the point of the (wireless) thermostat unit, since all SRTs are working as a thermostat and demanding heat individually.0
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Yes if you go into the settings page of the app, rooms and devices then select to the room you want to make independent (not the SRT tied to that room). Then scroll to the zone controller and click on No Zone Controller. This will make the SRT unable to call for heat but able to control the temp assuming the boiler is firing.
I have the same question with the wireless thermostat, I have it in a hall with a radiator with a SRT. Either can be the control for the temperature but for me the radiator works better. It does control the mode than the system works in and can be useful in a larger room (such as lounge) so that you get the temp you want.
Overall I have 14 SRT, 10 of which can control heating but this is on a modern modulating boiler and i have seen savings, annual total 24000 kwh down to 16000 kwh.
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The (wireless) smart thermostat (mine is wired) makes the physical connection to the boiler in order to turn it on and off. I'm not familiar with the wireless version, but I presume there is a wired component connected to the boiler and a wireless component that you can place anywhere you like. e.g. the boiler might be in the garage or loft and you don't care what temperature it is in those places. So you put the wireless part in the lounge or wherever you like in order to control the boiler. Then all the valves can also ask, via the bridge and wired/wireless thermostat, for the boiler to be turned on.
Without some sort of Tado smart thermostat Tado would not be able to control the boiler at all. You could still have the SRTs with a complex heating schedule, but they'd need to rely on something else to operate the boiler - like the original non-Tado thermostat. Then they would all be independent by default because they would have no control over the boiler. They'd be by like dumb TRVs, but with the capability to be adjusted according to the schedule.
Assuming you do have a Tado smart thermostat, this is the "zone controller". i.e. the thing that controls the heating for that zone - the boiler. You can make individual SRTs independent within the settings for each room. Either they can be "independent" with no control over the boiler, or they can be linked to the "zone controller", which is connected to the boiler.
For example, here are the settings for one of my independent rooms.....
So my landing is independent. It can be heated whenever the boiler is on, but it cannot make the boiler turn on. This might be a good solution for unoccupied rooms such as spare bedrooms, utility room etc.. For my property everything is independent except the kitchen. This works perfectly, with very efficient boiler operation.
To illustrate how this works in practice, here is the Tado heating pattern for my kitchen on 4th January. You can see quite easily the pattern of boiler firing in order to maintain the target temperature in the kitchen. The pale grey bands represent times when the boiler is being asked to fire.…
Whilst in the lounge the room is wanting heat all the time, but can only receive it when the kitchen turns the boiler on. It's pale grey all the time. It wants heat, but must wait.
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Hello @Jana75 Welcome. No one size fits all. It took three months to figure out what worked well for us.
Looking at your Potterton Suprima boiler manual, it has none of the efficiency features that a modern condensing boiler would provide (SEDBUK 78.1%). This, I suspect, will affect the way Tado is set up to get the best results.
Individual room TRVs calling for heat will fire up the Suprima boiler and use gas at 15kW until the boiler stat kicks in. Thats's not very efficient. Newer modulating boilers will throttle back the gas usage. Our 14-year-old Baxi is 92% efficent and the 15kW version can throttle down from 15.4 kW to 4 kW.
I'd agree with @eezytiger , suggest setting your TRVs as 'independent' and rely on the room thermostat to 'call for heat'.
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Thanks very much for all of you. I will try to configure my setup as advised and will see the result. I assumed that my old boiler can be a bottleneck in this story. Worth to think about a replacement. Do you have any suggestion about the key specifications for a new system
boiler to consider?0 -
Having used combi boilers since 1988 I'm not sure if there are any special considerations for system boilers, but two features of look for are…
- Ability to use the digital interface with Tado rather than relay switching, which I'm forced to use due to the second point.....
- Ability to regulate CH output power down as low as 2 kW or even lower. For example, the minimum output of my boiler is 9 kW. Average heating needs through December were only 2 kW, with the worst day so far this heating season only requiring 3.6 kW. The 9 kW minimum output is forcing boiler cycling. A much lower minimum output would allow steady, (almost) continuous running, with more even temperatures, less noise and less thermal stress. With a condensing boiler this would also improve efficiency, with even lower flow/return temps.
But, if I was looking to replace my boiler any time soon I'd have to consider a heat pump rather than continuing down the fossil fuels route. Fortunately I'm not at the point, yet, where I need to make that choice.
Oh, and back to the primary topic title, here is my gas consumption (kWh) each year for the past seven full calendar years....
11,536 (2018)
11,294
10,762
13,102 (2021 - new double/triple glazing in July, Tado in October)
8,242
8,898
7,986 (2024)
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@Jana75 our Baxi Megaflo HE 28 system boiler is 14 years old and was selected by the installer. Other than a couple of minor repairs, that were identified during the annual service, it’s never failed. At the last service, the gas-safe engineer recommended it as trouble-free. (Fingers crossed). In the same time my sibling has replaced three boilers of lesser known brands. Another rellie with a new build has multiple big issues with ASHP, UFH heating, hot water, unreliable controls, etc etc.
For me, first principles of home heating are ‘efficiency’ and ‘reliability/repairability’. Most modern boilers are ‘efficient’. Then it’s picking a known brand that is reliable and repairable. In my experience, as a homeowner and installer (not allowed today) and family home heating repairs, I’ve had good experiences with older boilers from Potterton, and more recently from Worcester-Bosch and Baxi. Externally, heating controls from Honeywell Drayton and (most recently) Tado have been good too. Unbranded heating products from big internet suppliers may be cheaper, but have proved unreliable.
Our typical energy consumption for heating and hot water in 2018-21 was 29,500 kWh. With Tado: 2022 =19,600 kWh. 2023 =15,000 kWh. 2024 = 13,750 kWh.
Hope this helps.1 -
Hi, I set up all SRTs as independent with individual schedules and only the wireless thermostat can fire up the boiler. I will check if my gas consumption changes, hopefully it will. However I noticed some strange operation of my system. Eg the wireless thermostat is set to 20 celsius and the actual room temperature is 20.5 celsius, the boiler is firing up in every 5-8 minutes for 1-2 minutes and it is happening repetedly for 2-3 cycles. After the boiler shuts off, it fires up again even if no any temperature change based on the app. Is it normal operation? I am not sure why not the temperature drop triggers the boiler to fire up. So my boiler is on and off many times and by this way it is using a lot of gas, I assume. Any thoughts?0
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I’m curious how you @eazytiger use the Tado trvs to control the upper temperature when they are so inaccurate right next to the rad.
I find they are accurate when the rad isn’t on but as soon as it’s on they shoot up to 22-25 degrees fairly quickly and turn it off.
Using offset doesn’t work as it’s then wrong when the rad is off.
I now use the temperature sensors as the measuring devices to avoid this.0 -
When the radiators are by an external wall the readings at the SRT are a reasonable proxy for the room as a whole. I run my heating 24x7, with flow and return temps as low as possible and I heat the entire house fairly evenly, pretty much.
That means there is not much in the way of cold spots or hot spots throughout the house. Thus the SRT temps are not far adrift from room temps - within a degree most of the time.
The exception to the above is in rooms where the SRT is nowhere near an external wall and not subject to the cooling effect from a cold wall. For these rooms I need to add a couple of degrees to the target SRT temp. I do not do this through temperature offset. I simply raise the temp setting for these SRTs.
With a baseline target of 18C in most rooms it would be rare to ever see an SRT show a figure above 20C.0 -
Just to add to my previous reply, here's an example of the measured SRT temps from my kitchen yesterday. The SRT is mounted in the corner between two external walls, by the back door. Overnight temp was set to 17C, daytime to 17.5C. There is nothing wrong with the indicated temp for the room.
As the coldest room/SRT in the whole house, if this SRT is at 17.5C the rest of the house should be warmer. This is basically the SRT that is connected to the boiler zone controller and controls boiler firing cycles. It is also the closest radiator to the boiler, but no sign of weird temps being reported.
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