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.
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?
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.
@tomvoo thanks for detailed reply. I am also planning to buy a fancoil thermostat. The problem I have is that I am going to retrofit an existing fancoil. So, I won’t be able to place the thermostat far from the fancoil, I will have to place it inside it.
I wonder if it’s possible to achieve the following
I want to use the thermostat to control the fan and the switch of the fancoil
Then I want to put a separate temperature sensor in a nice farther place (probably an Aqara one).
Would it be possible to configure home assistant in such a way for it to use the separate temperature sensor for the temperature control instead of using fan coil’s built in temperature sensor, but still use the fancoil thermostat for controlling the rest?
Perhaps, there’s a better way to achieve this? The other way I was thinking is buy regular relays, and create a virtual thermostat in home assistant.
hey! I’ve done exactly that, my thermostats are inside the fan-coils but I soldered on a new temp. sensor with a 1.5m cable and placed it where the old fan-coil sensor was, somewhere near the air-inlet.