I’m trying to turn a 158m² apartment into a smart home, step by step, and one of the things I would like to achieve first would be smart heating control. Currently all my radiators are equipped with simple mechanical / manually controlled thermostatic valves, so basically I start from zero, and I would be grateful for some advice about which hardware I should buy to meet my goals. What I would like to achieve is the following:
- Temperature monitoring and recording: I would like to see the current temperature in each room on my UI (which, I guess, would be an OpenHab panel, or web interface), and also record how it changes over time. So in terms of hardware that obviously means I need a temperature sensor in every room. (Not all rooms have radiators - such as a storage room - but I still want to monitor their temperature.)
- Setting target temperature: For those rooms which have radiators, I would like to set a target temperature. Ideally there would be two ways to do that: 1. centrally from an “all apartment UI” (could be some actual panel or a web UI) and 2. in the room itself (and then only for that room and not the others).
- “Smart” target temperature regulation: For now it would be sufficient if I could set a time-dependent target temperature program, i.e., lower the temperature while I’m away for work, raise it when I return home, lower it further when I’m away for a longer period of a few days to weeks.
- Failsafe mode (optional): In case my apartment loses electricity, but the overall house’s heating still works (like in case of a blown fuse in my apartment), it would be nice if the heating system would still be operable (radiator control keeps its current target temperature, target temperature can be manually adjusted at the radiator) as if it were an ordinary “dumb” mechanical / manual setup.
I guess all but the last item are easy, just the last one makes me wonder which would be the best setup, in particular because I would like everything to be fully wired, for two reasons:
- No batteries: I have quite a few radiators, and having battery-powered devices attached to each of them would mean a lot of batteries to check and replace.
- No wireless control: I have no wifi at home (but ethernet connectors in each room which needs to be wired up, as well of spare room in cable conduits) and no bluetooth devices either. I prefer to have wired connections only.
I don’t mind some dangling cables connected to the radiators, since there are nearby cable conduits anyway where they can just “disappear”. So far it seems that there are two standard solutions to achieve my goals:
- Having temperature sensors in every room and electrically controlled open/close valves on every radiator, completely separate from each other (independent devices). So for each room I would get a temperature reading, and I could switch each radiator on and off by applying or not applying voltage to the valve actuator. Also each room would need an input panel if I would like to set the target temperature. The most simple way to connect them would probably to connect all devices to a common central control unit. But for the “failsafe mode” mentioned above it might be nicer to have, e.g., one Arduino or similar for each room with a backup power supply (USB power bank?), so that each room could still be operated on its own (provided the valve actuators don’t consume too much power). Without such a backup, all valves would just close (or open) until power is back / fuse is replaced, which could be unpleasant.
- Having each radiator equipped with a thermostatic valve whose target temperature can be set both remotely and locally. That would actually be ideal for me, as far as I can see now. Basically it could work just like the “dumb” mechanical valves I have now, with the possibility to adjust them directly on the spot, but with an additional wired input channel to “turn the knob” remotely as well (and even better also with wired output channels telling me the target temperature, if somebody changes it locally, and ideally even the current temperature). Also it would be nice if they (mechanically?) kept their thermostat function if power drops. I have found quite a few devices which apparently work like this, but all of them are wireless, which means batteries + wireless control, and so they are off the table for me. (And I assume the thermostat / temperature regulation in those is also gone if batteries are empty?)
Does anyone have some suggestions or opinions on my setup? Suggestions for devices which could help me to build the latter solution, i.e., thermostatic valves with additional wired control of the target temperature (if possible still working as “dumb” mechanical thermostatic valve if power fails), would be most welcome, since I have not seen any such device (maybe there is none). But also any other advice would be highly appreciated.