Tado and Daikin Altherma 3H HT Air Source Heat Pump

I am going to be replacing a traditional gas boiler and hot water tank operating in 'call for heat' mode. I had initially considered a modern gas boiler such as Worcester Bosch operating in modulating heat control mode along with matching solar thermal panels.

However I am now considering instead getting an air source heat pump system connected to radiators. I originally discounted this approach both because the early systems had a single massive floormounted internal unit that would typically be fitted in the kitchen and because originally they were very expensive.

There are now air source heating systems which combine a smaller wall mounted unit roughly the same size as a standard gas boiler with a separate hot water tank which I am hoping to fit in the location of the current standard hot water tank. On top of this improvement, with an air source system I will not need to buy and pay for the solar thermal tiles I had originally intended and the cost of air source heating systems has come down although still expensive.

Tado tell me that their system will work with the Daikin Altherma 3H HT I am considering getting. I was wondering however if anyone here has experience of using Tado with air source heating systems and even better any experience of this Daikin system.

See - https://www.daikin.co.uk/en_gb/product-group/air-to-water-heat-pump-high-temperature/daikin-altherma-3h-ht.html

Do such systems operate in a modulating manner?

This system and some other air source systems can also operate in a 'reverse' mode whereby they cool the house. Can Tado handle this? Would this involve also using their Air Con product?

Can one room be cooling whilst another is heating?


  • I have been thinking about just this setup for later this year myself actually so, although I can't offer any experience, if you do go for it I'd love to hear how you get on!
    Have you already got solar PV? Or planning to add it at the same time? I'm hoping I'll be able to get 4kw of solar PV at the same time as replacing the gas boiler.
    And which water tank are you thinking of? I'm considering the Mixergy tank, but not sure I can justify it
  • @stevenumber11

    I am planning to get Tesla Solar roof files when/if they eventually start selling them in the UK. I am only able to consider this because I would do it at the same time as replacing my roof.

    It is my understanding that the way this and other air source heat pumps work is that they have an outside unit (big) which captures the heat from outside air, it sends it to - in this case a small wall mounted unit which is the main controller, internal pump, etc. this then sends it to their own matching water tank for storing the heat. I therefore do not believe it is also necessary to have a traditional hot water tank as well since the entire air source heat pump system does this task.

    Older and still current larger systems combine the internal controller/pump with the tank in to a large floor standing unit the size of many fridge/freezers which in my case would take up too much space in the kitchen.

    They show their tank on page 11 of their brochure which is available via the following link.

    I am hoping this tank can be located in the same place as my current traditional tank.

  • @jelockwood
    Although I expect Daikin would love everyone to buy their water tank as well, I'm pretty certain there is no need to. My reading of the way they advertise the heat pump is that it's designed to be compatible with existing plumbing. So you should be able to connect it to any water tank you like as far as I can tell. If they've somehow engineered the wall mounted unit to only be compatible with their own water tanks, I have to admit that might put me off
  • @stevenumber11

    I will have to wait and see what they say when I eventually reach out to them or a reseller.

    The tank in this case would be used to store both hot water for taps etc. and I am presuming hot water for the heating i.e. radiators. Again I have yet to speak to them and have never previously had an air source heat pump but I feel it is more like a combi boiler system.

    Since it cannot heat up on demand or instantly from gas it has to extract heat from the air and store it somewhere so it is available for use.

    I need a new tank anyway.

  • The hot water tank does not need to supplied by the Heat Pump manufacturer. Mine is by World Heat Cylinders and preplummed with all the LG (in my case) stuff added. It also combines the main hotwater and a buffer tank for the Central Heating.

    You can also have the cyclinders custom made, no idea on the costing but they can be made to fit whatever space you have available. Then there is the pressurised and vented options. I've added pictures to show you the before and after main tanks.

    I also have two 25l expansion vessals for the hot water and heating systems so there is potentially more than that one tank.

    Don't forget the green homes grant, you maybe able to get a decent contribution from the government. For us it was £5k which made the project viable.

  • Wow, that's some water tank, @armsinit!

    So, do you have a tado thermostat controlling your heating with the LG Heat Pump? How's it working for you?

  • That tank is a beast! Any ideas how much that weighs when full?
  • @gary333 333 Ha, no idea on the weight, there is a double joist there so it should all be good.

    @stevenumber11 They are working really well together. The water is left to the LG, Tado has nothing to do with that. It just heats up when the temperature in the tank drops.

    Only problem I had was in one room the radiator is not large enough to warm it to the desired temperature. It's in the kitchen and not enough space to increase it's size. I took that off the bridge so it can't call for heat which saved me a bit of money. It's on there is because of people opening windows and the door to the garden.

    Before the heatpump we had an old dumb boiler control. Some rooms would not get warm while others would overheat. After the switch everything is at a good temperature and stays that way.

    There is a big difference between having smart thermostats in isolation mode and connecting to the bridge and deciding when the boiler fires up. I would recommend that to anyone in terms of comfort in your house, I don't think the brand matters at all.

  • @armsinit

    I am guessing you mean there is not enough room width or height wise to fit a bigger radiator.

    It maybe however a 'thicker' radiator might be possible. Standard typical radiators can be either a single panel with fins on the back or two facing back to back. However it is also possible to get a radiator designed like old style cast iron radiators and these can have 2, 3 or even four columns with it being thicker the more columns it has. See the following pictures.

    Above is a standard single panel radiator.

    Above is a standard double panel radiator.

    Above is a four column 'cast iron' style radiator. As mentioned these are available with 2, 3 or as the picture above four columns. (Look at the end view.)

    You should get a figure for how powerful a radiator you need in this room, here in the UK radiators are measured in BTUs - British Thermal Units.)

  • @jelockwood A thicker radiator wouldn't work in the space either, it's already a Type 22 (K2) . As we are normally in that area after the food has been cooked that does make it comfortable enough.

    Our bedroom which is in the loft does have a type 33 (K3), that took 4 guys to get up there as it was over 100kg and 2m long.

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