Domoticz and smart thermostats

[slagterbas]

Hi all,

So, I am fairly new to Domoticz and just got my Raspberry Pi up-and-running with Domoticz since a couple of weeks. Since then I added a couple of Fibaro dimmer modules and switches to control to lights. All cool but...now I want to control the heating with Domoticz.

I currently have a fairly simpel Honeywell Modulation (T87M1003) thermostat which is, as far as I know, not smart at all. I am interested in using the Fibaro thermostats (https://www.robbshop.nl/thermostaatkraan-fibaro) to separatly control the temprature in (some of) my rooms. Since we have a fireplace in the living room I end up having a cold room for my baby when it needs to go to sleep.

So, now is my question; what is the best, easiest, cheapest way to go with this?

[heggink]

The Popp and Honeywell thermostats work fine with domoticz. I have one of each and control them thru domoticz. I also have a nest thermostat in the living room that is supposedly smart but not smart enough for my liking so I neutered it and now control it from domoticz as well.

[slagterbas]

@heggink. Thanks. Can you explain a bit more on how you have this set up?

[heggink]

Sure. I have 2 rooms (studies) on a separate heating where the popp controls the room's temperature. I created a dummy switch that triggers a script to set the temp to 21C or back to 15C. I also have presence detection that ensures that the room is never heated when the person is gone.
The Nest controls the rest of the house. I have a dummy thermostat with a weekly programme. As soon as the dummy changes, a script sets the nest to the required temp. That's pretty much it. If you have any other questions then just ask.

[slagterbas]

@heggink ok, so first things first. How can I set the temperature to a specific value? I imagine that I need to set it to 21C if I want to use the specific controls in one of the rooms otherwise there will be no heat at all. Like I said; I have a fairly simpel Honeywell thermostat. How can I control this with Domoticz?

[slagterbas]

Bump

[heggink]

Ha, wintersport...
z-wave radiator thermostats can only control if heated water is supplied. For the 2 that I use, I have the main thermostat on 24C so that I can control individual rooms up to 24C. I use dzvents scripts to set the z-wave radiator thermostats to the required temp (device.updateSetPion(required_temp)).

Your challenge is that you probably have a honeywell that controls the entire house so unless you attach z-wave valves to all radiators, you will not be able to control individual rooms without overheating the others...

[philchillbill]

The problem with a main thermostat in the livingroom and separate smart radiator valves (TRV) is that the living room will always have to demand heat or else the boiler will be off when your Fibaro valves open up the radiators. I have a Honeywell Evohome system where any TRV can ask the boiler to switch on. In just over a year my heating bill has dropped to 60% of what it was PLUS we always have the right temp where we want it. I can even ask Alexa to set the temp of my upstairs office to 22 deg before I go up and it will be warm. Most importantly, all the other radiators in the house will stay shut off so (1) I'm saving money by not having to increase the living room in order to get the boiler to fire, and (2) the office will heat fast because it's the only radiator getting the hot water being pumped around.

The paradigm of the main thermostat in the living room being the only device in the house that can get the boiler to supply heat is *so* 1987...

[slagterbas]

Thanks for the responses. So if I understand it correctly I need to have radiator valves for all my radiators plus something that switches on my heater when needed (in case any of the valves want to heat a room). I understand that there is no 'in between' solution where you can keep the regular '1987' thermostat setup and also control the temperature of a single room with a smart valve. Now...let's assume I bye a box full of valves and set them up on all my radiators. What will I need to do to switch on the heater when needed. Do I need a smart themostat like a NEST or ANNA thermostat for this?

[philchillbill]

If you get an integrated solution like Evohome there's a so-called 'boiler relay' module to control demand (which can be an on-off or an OpenTherm variant). OT is better because it allows modulation of the boiler but on-off is simpler to hack. An on-off boiler control just shorts the two wires together in the wall thermostat to turn on the boiler. If you're happy with your old wall-mounted thing in the livingroom and it's an on-off type, you can just put a z-wave relay in parallel across it at the boiler upstairs and it will turn on the boiler for you - just be sure to NEVER forget to turn it off using z-wave when the boiler should go off again as the wall 'stat in the livingroom will do nothing when that relay is closed and you will pump warm water around your house forever...

You might be better off forgetting about the Fibaro stuff until they introduce a boiler relay and therefore a full solution. If you don't want to wait then get EvoHome, Daalderop Spider, or Tado gear instead. In the long run, an integrated system is much more wife-friendly and will save so much on energy bills it will pay for itself in a few years. All of these can be smart-phone controlled too which is a nice bonus.

[jake]

Too bad that the open therm gateway OTGW can't be used to turn on the boiler, unless you put the room thermostat setpoint to a high value

[slagterbas]

Thanks! Sounds like a solution like Evohome is the way to go for me.

[berkens]

An other option is a weather-dependent thermostat in the livingroom. The outside temperature sensor informs the thermostat about how cold it realy is outside. The watertermperature is proportional higher/lower when the outside temp changes.

In "Optimal Comfort mode" the watertemp is high enough to heat the house. With the valves on the different radiators in studyroom, bathroom, babyroom a z-wave heatcontrol valve is controling the room temperature. In the hall you have a partly open manual heatvalve to protect the waterpump from stalling. Or a bypass-valve far away from the heater protects the pump.

An example of such a thermostat is the Honeywell Chronotherm Touch Modulation with a remote temp sensor installed. You need a modulating heater to work with this thermostat.

Unfortunenatly there isn't a Z-Wave version yet.