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New Device - Tado Immersion Hot Water Heating Controller


Many homes having a hot water storage cylinder would also have the hot water heated by an element in the cylinder either as standard or as a backup option to the gas heating system.

I wanted to raise this subject here to help gauge if there is actually an interest within the community of Tado users?

Do you have a hot water storage cylinder?

Does it have an immersion heater element either as the main heating source or as a backup?

Would it be useful to include this control within the Tado App either for daily hot water heating or just for summer when the gas heating is off?

Would welcome your feedback.

Many thanks,


9 votes

Active · Last Updated


  • davidlyall

    Tado can already turn on an immersion heater if you have a contactor wired between the tado HW relay and the higher load of the immersion.

    I expect it's quite a niche request as I suspect few people will use electric immersion heaters as a primary source due to the high cost of electricity compared with gas

    However, I do wonder if there would be a market for tado devices that could control electric heating systems with higher loads than 3A (i.e. most!). I have a rental property that uses electric heating controlled by wireless timer/thermostats. They're not internet connected so control is limited to the schedules set

  • I wish Tado had such a device. I am fully Tado'd up except for the electric UFH in my bathrooms. I bought one of these a week ago:

    Have set up some homekit automations so that it turns off when away etc. It seems pretty good, schedule is controlled by the Meross app etc. Lacks any history or graphing and I'm not sure whether there is any API. I presume it is not an issue when the internet is down either.

  • Yes. My overnight electricity is about 1/2 the price per unit of my gas. So, yes, hot water heated by an immersion, scheduled overnight = a good thing here at least. Retain the existing gas boiler controls for daytime (boost if needed) as daytime electricity is way more pricy than gas.

  • I'm interested in a control system being able to control my (currently back-up) immersion heater in my water cylinder. My boiler is oil-fired and connected to a Hive system currently. Hot water, heating and plugs are supported but not the immersion heater. Octopus smart tariff would allow immersion heater to heat the cylinder overnight much more cheaply than via my oil boiler via its heat exchange coil.

    I am happy to replace the Hive system, but I am struggling to find a replacement control system which includes immersion heater controls. My immersion heater has its own thermostat, and is controlled by a wired "on-off" manual switch. Im looking for a system which allows scheduling to switch the immersion on and off via its App.

    Hive don't appear to have any interest in adding immersion heater controls.....what about Tado?

  • DGG

    DHW Tank Temperature control

    I have a Baxi 824 system boiler sited close to the domestic hot water tank. It runs both the heating and domestic hot water perfectly for our requirements with the boiler temperature set at 50 degrees centigrade, and it runs very efficiently with Tado controls.

    There is no separate temperature setting for DHW on the Baxi 824 boiler.

    I understand that the domestic hot water tank should be kept at 60-65 degrees to kill of legionnaires etc., therefore this is a concern.


    1. Top-up the water tank temperature with the immersion heater to keep it safe. If this can be integrated with Tado then synchronising the pre-heating of DHW with the boiler before calling the immersion heater to top-up the temperature would be straightforward. This can be achieved with timed immersion heater control but integration would provide visibility and a manageable process.
    2. Can Tado request an adjustment to the boiler flow temperature for Heating and DHW via the Tado call for the service? If not, then surely this should be a consideration for future designs?
    3. Is there aTado temperature probe to attach to the domestic hot water cylinder to show the actual DHW temperature? THIS WOULD BE A SENSIBLE AND VALUABLE CONTROL FOR THE TADO SYSTEM TO ENSURE THAT THE DHW SYSTEM IS SAFE. It is difficult to guage the actual tank temperature achieved from the domestic hot water tank thermostat and boiler temperatures. If there isn't a Tado device then can third-party devices be used?

  • You don't really need to store it that hot. Modern thinking is a regular cleaning cycle to raise the temps once a week or so.

    Tado don't prioritise those with hot water stores, so seek some other solution.

  • Ive just had solar panels installed. Heating the hot water when I have excess energy being produced during the day is a way of storing energy and getting the most from it. If I don't use the energy, the most I get paid for it is 14p a unit. It costs me more than that to heat my hot water with gas so it would be really useful to be able to turn on and off the immersion heater without having to dash upstairs and flick the switch every time the sun comes out.

  • johnbur
    johnbur ✭✭✭
    @SLamps what you want is a Solar Diverter
  • royi
    This is interesting, since installing the Wireless starter kit. I've just noticed that my hot water cylinder (with it's own thermostat) has a switch next to it in the airing cupboard, which acts as a backup immersion heater.

    I've always used the gas boiler to heat the hot water, but will come in handy if something's happens with the tado system and can continue to have hot water. But it would good to have this extra function on the app.
  • Humb3rThump3r
    Hello, Lots of people have inquired about adding immersion heater control to Tado, sighting immersion heaters as aback-up or alternative to firing a boiler to provide hot water, perhaps favouring a ‘Time of Use’ electricity tariff vs oil or gas. The water could be heated to a lower temperature with a regular anti legionella cycle to keep things safe.

    Tado have cited that they only switch low current control circuits.

    Perhaps Tado could talk to T Smart.

    Tado have what T Smart don’t I.e. a great integrated App and ecosystem, T Smart have a WI-FI enabled cylinder thermostat.

    Perhaps you should talk?
  • Would love a tado device with this feature - particularly as heat pumps often have backup immersion heaters. The need is probably going to become more prevalent rather than less
  • Aiky30
    edited March 11

    More people commenting than upvotes ...

    This feature is interesting to me as I am on Economy 7 and would greatly benefit from electric water heating at night and gas as a top up.

    I will probably buy a timer spur to auotmate this, although it would have been really nice to use the app and equipment I've spent nearly £1000 on with Tado!

    Wish I had gone with the super configurable Honeywell solution now. :-(

  • wateroakley
    wateroakley ✭✭✭
    edited March 13
    Our rellie uses electric timers for the immersion heaters on the HW tanks and Tado controls for heating.
    We have recently installed solar panels with a myeddi for hot water. It’s programmable to use overnight cheap leccy from the grid.
    Tado is now set for the gas boiler to heat the HW for just one hour in the morning and free leccy heats the HW during in the day.
  • legend99
    I'm using Sonoff to control the gas heating while I have tado on the heating. However, one issue I've realised is basing what happens on temperature. The thermostat probe pocket is down about 1/3 of the way from the bottom of the cylinder - that's what's recommended too to be fair. I use that, with a Sonoff probe in it connecting to a TH16 controller to control the call to the gas boiler for heat. However, the immersion element is one that goes in at the top of the tank. So it doesn't heat water near the probe. And hot water rises. So on the one hand, the immersion, running off cheap overnight electricity, is heating the water in the top half of the cylinder to 60 degrees. But the probe doesn't see that. And if I keep my Sonoff routine to call for heat when the temp is below say 40, then it's a waste as there is enough water already in the cylinder for a shower. I guess it's the old problem of not knowing how much hot water you have in your cylinder as it stratifies into layers from hot to cold....?