Looking for advice: Home heating / cooling with heatpump and fan-coils

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Hi guys,

I’m breaking my head over this for a long time now and I’m looking for advice/help from the community on what you guys think might be the best solution for my situation.
This is what I have:

  • A house with around 400m2 heating/cooling surface
  • 4 guestrooms for rent
  • Every room has at least 1 but most rooms have more than 1 fan-coil heater. Some rooms have up to 6. The guest rooms all have just 1 fan-coil.
  • Bathrooms have a traditional radiator
  • House has 3 main heating zones: ‘private’, ‘restaurant’, ‘guest-floor’.
  • A heatpump (heat/cool) with a 150L buffer vat.
  • Each zone has it’s own circulation pump which controls the flow of cold/warm water
  • Hot water for showers is using a seperate heatpump and it’s not part of this particular challenge (works fine).

My requirements:

  • Guests should be able to control climate in their rooms but should be able to be overridden globally.
  • I should be able to both manage cooling and heating (not at the same time, just at different moments of the year)
  • I want to have “Room climate” meaning, that regardless of the amount of fan-coils I have in the room it should have 1 setting per room.

What i tried/have:

  • I have a tado set-up which kinda works for heating. I can say: When zone x calls for heat, switch on pump.
  • The fan-coils are dumb but have a temperature sensor on the radiator and turn on when they either detect a value below a certain temperature (cooling mode) or above (heating mode). I’ve used this with Tado succesfully without controlling directly the fan-coils. When the heating turned on in my old setup with boiler it would start circulating hot water and the fan-coils would turn on and switch off automatically based on the water temperature. Obviously with a big delay.
  • Tado does not do cooling…
  • Circulating pumps I already have Shelly switches connected
  • Heatpump has a Home Assistant compatble controller which I can control 100%
  • Preferably a fallback mode for when HA goes down but I understand this might be VERY hard to achieve.

I know this is a rather complicated setup but I would love to hear your ideas.

Thanks so much!!

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Sorry @tomvoo for an unhelpful reply, but I am looking to achieve a similar setup (at a smaller scale) for my self build project. Can’t bare the thought of bringing in anything which I can’t control via HA! Have you had any luck since your post?

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hey Nick yeah I did figure it out somewhat. The main thing i that I found cheap BHT-002 Tuya Thermostats for the fan-coils on Aliexpress (https://www.aliexpress.com/item/1005006749028959.html?spm=a2g0o.order_list.order_list_main.5.77c61802o2gGX9) that I was able to serial flash. (The two i bought last year I was even able to flash using tuya-cloudcutter but the later models I had to serial flash). I also have zigbee Sonoff TRVs for the radiators.

I flashed these with ESPHome, there is a template sepcifically for this model.
That means I can now control every fan-coil from HA. I grouped them into the zones that match my pumps (kitchen/restaurants, guest rooms, private). When any of the devices request heat in a zone, the pump switches on. This kind of works but can be further optimized which I haven’t done yet.

  • I still haven’t found a cheap generic dumb thermostat which non-tech users can use to set the room temperature. It just needs to be a device with a display, 2 buttons and a sensor. I doesnt need to be a thermostat but I haven’t found this yet.
  • The BHT-002 does not have a state that says “heating” or “cooling”. It’s possible to achieve this but you need to solder. So i’m now just doing: if ambientTemperature - 0.5 < targetTemperature: heating = true
  • It takes some time for the system to come up to temperature and you don’t want the fan-coils to start blowing if the temp is not > 25C yet so I still need to make an aitomation for this based on the sensor in my hot water puffer.
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Well done! Thanks so much for sharing.