TLDR:- Weird heating setup and not a normal application - im looking for a smart
thermostat reccomendation with a “Demand” output entity but works offline.
OK - This is a weird one, and definitely not your usual “Which thermostat” question!
System:-
We have our home and hot water heating supplied by 2 air sourced heat pumps.
We control this via Zigbee switches that drive the heat pumps and valves.
Why two?
- They were cheap.
- Small and light enough to hand carry up to the roof!
- They were really very cheap.
One is configured to drive the heating only.
The other to drive either the hot water or to boost the heating via control valves (One heat pump output is not sufficient on colder days).
We live in an open-plan appartment in an old 17th century stone building so the heating has one zone, and no thermostatic valves (Nicely optimised for the heat pump source), and usint the Tado thermostat and Octopus Agile pricing setup, its been working really well and cost effectively.
As the building has massive thermal mass, and we live in it more or less 24h a day, the “smart” thermostat isnt so useful for temperature changes because we are in/out of the house for a few hours - the response time is too long.
The control system on the Grant Aerona 6 heat pumps is really basic, and TBH, not very good. It only gives me an “on / off” control of the heat output, and the reccomended installation instructions leave a lot to be desired.
I’ve been using the “demand” entity from the Tado thermostat to decide how many heat pumps to engage (Based on an arbitrary threshold of demand percentage), and its been working great, until recently… TADO now limits the API calls, and logs me out - then it all disappears…
The Tado has actually been working really well this way, and temp control has been flawless for two years, with the external temperature integration, and the thermostat learning the response of the building. But the latest API issues have meant I’ve had to revert back to the contact output from the TADO to have reliable heating.
I’ve tried using the homekit integration, but it doesnt let me see the “demand” entity, - I dont even see when the heating or hot water is switched on!
Before I end up going mad writing my own blue print, or doing some weird connection setup to enable HA to sense the contacts on the Tado thermostat, does anyone have a reccomendation for a smart thermostat (Or a nice blueprint) that works if the internet fails, and has a decent “demand” output?
If anyone has questions about heat pump practical applications, let me know.
Cheers,
Mike.