Bring back Modulation (OpenTherm) to their wireless thermostat (UK)

Currently only the wired version supports modulation (OpenTherm) where as the wireless version in the UK ONLY does not support modulation. The EU version does. I think Tado should bring the EU version features to the UK product. It's essential for energy saving and would add more competition to the market and make Tado even better and more flexible.

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  • I read somewhere on here that Opentherm support was removed because the feedback from UK installers was that it was too complicated and they didn't understand it....
  • @johnbur it more likely that the UK installers are just lazy b***ards, and can not be arsed with "OpenTherm" setup.

  • What is Open Therm & what are the benefits?
  • OpenTherm is a control protocol that most modern boiler have, it allows the thermostat to have more control over the boiler to modulate it, instead of the boiler just been turned on or off (with the burner at full or off), it can control the burner to regulate the flame intensity so if the room only needs a little heat say 1 degree to reach target temp, the boiler will only heat the rad water a little so target temp is reached in most efficient way, instead of boiler heating water to max flow temp.

    it can do a lot more, have a read about it here:

  • So is it official that the wired version does opentherm ?


  • The wired thermostat has Opentherm support. The uk wireless receiver doesn’t.
  • The wired thermostat is compatible with Opentherm and many other digital buses (when wired to the boiler), and has been for many years.

    The 'old' Extension Kit we used to sell is compatible with Opentherm and many other digital buses.

    The 'new' (2019?) Wireless Receiver (the replacement of the Extension Kit) has 2 versions:

    • EU version. Compatible with Opentherm and many other digital buses. Has 1 relay for legacy boilers.
    • UK version. Has 2 relays for typical UK heating systems (1 heating, 1 hot water). Not compatible with Opentherm or any digital bus.

    Introducing 2 versions of the Wireless Receiver has obviously been extra work and effort from out perspective. We did this after a strong demand from the UK market for a simple to install, simple to configure device. UK installers were struggling with the configuration and wiring options our then-current devices offered. Because we noticed the adoption of Opentherm with the then-current Extension Kit in the UK was close to zero, we removed it to achieve extra simplicity for installation/wiring/configuration.

    On the other hand, within the EU roughly no one is using 2 relays and bus adoption is high. Hence the other Wireless Receiver on those markets.

    To not confuse customers, we simply offer 1 Wireless Receiver per market.

    We will keep monitoring the demands of the market though. Also with x-to-water Heat Pumps which, depending on the market, tend to be controlled by a digital bus like Opentherm as well.

  • As a prospective new customer looking to move from Hive and gain modulation, this is incredibly disappointing. I'd also argue it's difficult to determine that tado doesn't support bus on the wireless model in the UK.

    How does this article not mention it? How does the product page not mention it? Does the image in the installation section show the data compatible device?

    Can you confirm that the Wired Thermostat supports EMS?

  • Rob
    Rob | Admin
    edited September 2022


    As I wrote above, your suggestion is exactly what we did in the past in the UK. We had the Extension Kit with 2 relays and bus support. This strategy did not work, many installers in the UK simply could not handle the wiring and configuration options our Extension Kit provided. They ignored our manual, 'knew better', botched the installation and left. Resulting in frustrated customers with no heating. So we changed strategy, and the feedback has become much more positive. To be fair, we do get negative feedback for not offering bus in the UK any more. However, the general gist of the feedback we get from the UK is much more positive nowadays.


    I understand your frustration. From a feature perspective it's a downgrade, I fully see that. But from a user satisfaction perspective (for the whole country), it's an upgrade.

    About EMS: There are multiple versions of the EMS bus. Depending on manufacturer and age/generation of the boiler. The wired thermostat (and Extension Kit and EU Wireless Receiver) supports multiple versions of the EMS bus, but not all of them. To be sure about your individual situation, please contact support and name your exact boiler model (and maybe the old stat you want to replace).

  • It amazes me that the company listens to the views of installers who think connecting 2 OpenTherm wires is confusing? Also why do they not get confused when installing the wired thermostat OpenTherm? I heard a different story in that a lot of people couldn’t get OpenTherm to work using the 2 channel wireless receiver, and Tado were getting so bogged down with support queries and complaints that they dropped it in the U.K. rather than sort it out.
  • mr_b
    edited October 2022

    I was shocked when I discovered that Tado didn't support OpenThem in the UK.

    It seems the company's position is that some UK installers are not as competent as ones in the EU so they dumb down the product for everyone in the UK. Huh?

    Given the energy, cost of living and climate crises, it should follow that the responsible position should be to make the installation easier so that mistakes are not made and the most efficient, energy and cost saving solution is possible.

    Other controllers support Opentherm and I've not heard that lots of their installs are botched, so Tado sticks out (and not in a good way) for taking this very odd stance.

    Oh and I tried contacting support about how to enable OT with my wireless system and they would talk to me as I wasn't a "professional installer", not even to say if I needed different kit. My "professional installer" didn't know (despite being a Living Lab scheme installer).

  • I'm reading this as I've just fitted a bunch of Tado SRVs and am looking at the Tado wireless smart thermostat to replace my Nest stat and give more control of the boiler through the SRVs.

    I'm shocked to find that this will not support open therm, which was a doddle for me with my DIY skills to set up with my wireless Nest stat. Looks like I may have made the wrong choice of system.

    Can you tell me why I should still proceed with replacing my lovely Nest stat with the Tado one?

  • @Folkranger unless you want the trvs to be able to call for heat from the boiler (via a Tado wireless receiver or wired thermostat) I couldn’t give you a good reason to change.
  • My main reason would be because the thermostat, located in the lounge, tends to shut off during the day on sunny days. This shuts off heat to the rest of the house.

    Having just added the Tado SRVs, I'm currently fooling the system by having the Nest stat set higher than the SRVs in the lounge so the lounge SRVs close off with the sun but the Nest stat keeps going to heat other rooms. Not good practice as there is nothing other than the schedule to stop the Nest stat from demanding heat (a towel rail in the bathroom can take away some of the heat but........?)

  • Yup, not ideal - I would put a manual trv on one of the radiators and leave it fully open (or remove the trv altogether) in that case.
  • @Rob As a new user I just want to add to this post that my reason for selecting Tado after doing my initial research was its ability to talk to Worcester Bosch's EMS bus on my slightly older boiler. It has been frustrating to discover along the way that I can't buy the UK version if I want this feature and so I am trying to source the EU version or older extension kit.

    The extension kit pops up on eBay but so far I have been unable to secure one. I had also planned to buy the EU version from the Ireland shop or UK shop but both are now sold out.

    As a fairly techy consumer i have done my research and I want this product but you are making it very difficult. Please just get this sorted out.

  • So Tado Thermostat doesn't give an open therm boiler the temperature information it needs to work efficiently. It also doesn't do home and away control (properly) unless you pay monthly. WTF is going on?

    It seems that I now have seven expensive smart TRVs and a bridge, but no way to join the dots and have a fully functioning system that gets the most out of a modern boiler.

    Comment TADO?

  • johnnyp78
    johnnyp78 ✭✭✭
    edited October 2022

    Just to make it clear - the Tado wired thermostat (which also works wirelessly) does have digital connections including opentherm. It's the uk wireless receiver that doesn't.

    I've got a certain amount of sympathy for Tado charging an optional monthly subscription if that goes towards R&D, though it's debatable whether that happens.

  • I've got nowhere sensible to put a wired version (not wired in).

    When you say also works wirelessly, does that mean buying another bit of kit? How would I do this?

  • If you want Opentherm and wireless control, you can either use a wired thermostat to control the boiler and a wireless temperature sensor, or a used extension kit and a wireless temperature sensor, or an eu wireless receiver and wireless temperature sensor.

    wired thermostats can also work wirelessly but are more expensive to buy than wireless temperature sensors.
  • Thanks. Sounds like two or three sledgehammers to crack one nut.

  • In fairness to Tado, you can get a system that works with Opentherm, has trvs that can call for heat and has the option of auto geofencing. That’s more than most of its competitors, with the possible exceptions of evohome and netatmo.
  • mr_b
    edited October 2022


    I have the Starter Kit – Wireless Smart Thermostat V3+ and smart TRVs. What kit do I need to gain OT capability from

    I find the product capabilities as listed very confusing. A feature comparison table would be useful.

  • The info is here
  • The info doesn't say which product I need to add to my existing system to make it OT compatible. For example it says Wired thermostat has OT but I have a wireless thermostat. If it's wired only then I guess it's incompatible with the smart TRVs?
  • Are you in the Uk? What is connected to your boiler? The older extension kit or the newer wireless receiver? If it’s the extension kit then you’re in luck, it has digital connections. If it’s the wireless receiver then it doesn’t and you will need to replace it with either an extension kit, a wired thermostat or an eu wireless receiver.

    If you have a system boiler with hot water cylinder you’re unlikely to be able to use opentherm. If you’re in Europe then whatever you have connected to the boiler already has opentherm.

    I agree that Tado should make it clearer which equipment does and doesn’t have digital connections.
  • swwils
    edited October 2022
    All you need to do is offer a UK extension kit that has 2 relays and digital bus - BUT it's configurable to have relay at the same time as digital bus.

    Then we can actually do X plan and PDHW on our crappy boilers that don't expose outputs when working via opentherm.

    Bonus points if you offer 3 relays and digital bus, then we could actually convert, with minimal fuss; these ridiculous 2 zone s plan systems that have been installed by idiots for 10000 years to something efficient.