Welcome to the forum. You’ve got questions, I’ve got some answers. 
Question 1
Yep. I’m still making them and offering them up for sale. I also offer kits for people who just want the parts and want to assemble them themselves.
Question 2
Yes, you can set a range and it’ll stay within that. In the UI, it’s a matter of turning on the heat at one set point and the cooling at another.
You’re correct about us not having scheduling outside of something like cron jobs. Cron jobs were never an ideal solution, but they worked well enough that it zapped my motivation to try to implement it in OpenHAB.
Question 3
I can confirm, you’re good to go.
Question 4
I do plan on using and supporting this project. Here’s the scoop on the hardware, software, and what is planned for the future.
The hardware is officially supported by Raspberry Pi and will remain in production through 2030. Honestly, that’s more of a guarantee than most things available. The rest of the electronics are basically just relays to switch the HVAC on and off, a temperature/humidity sensor, and a power converter to convert the 24V AC the HVAC uses to the 5V DC that the thermostat needs. So there won’t be any major changes needed there in the foreseeable future. And since that is all open source, you’ll always be able to make more of those boards.
As for the software, I’ve been keeping the O/S up to date to make sure we can always get security patches, so we’re good on that front. But the elephant in the room is OpenHAB, which is only a few years old, but unfortunately that project doesn’t offer long term support. Second, they were pushing the memory limits of what the Pi Zero (or Zero 2) can do and they’ve only gotten more memory hungry over time. On top of that, they use versions of Java which require a hardware FPU. The original HestiaPi thermostats had the Pi Zero W, which doesn’t have an FPU and that worked fine at the time because it can just be implemented in software.
I am absolutely adamant that we continue supporting the old hardware (Pi Zero) as well as the new (Pi Zero 2). I’d like to have the same image run on them both, but given all of the above, this is complicated.
Here’s what is being planned/done to address the situation:
- All units that I produce now have a socket so the Raspberry Pi can be easily replaced. This allows for hardware upgrades in the future as long as they keep the same headers (which they did between the Zero and Zero 2 and I expect they will continue doing going forward). The original model had the Pi soldered in, which can still be replaced, but not easily.
- Continue focusing on updating the O/S (using the version of OpenHAB that can run on all the hardware). This is what I’m actively doing right now.
- Creating an option to use the existing HestiaPi connect to an external OpenHAB server (and possibly HomeAssistant, depending on how easy it is to be compatible with both). This is probably next after I get caught up on O/S updates.
- And something that @HestiaPi is working on a very simple model (the Hestia32) thermostat which will work as a simple thermostat by itself, or can connect to an external server to get wifi connectivity and advanced features
Question 5
Not in a self-contained unit as far as I am aware. Home Assistant which has gained popularity, but it’s just the software. There are plenty of write-ups on how someone made their own thermostat from a Raspberry Pi or ESP32, but they seem to mostly be personal projects (example).
In my mind, what sets the HestiaPi apart is:
- It doesn’t require an external server
- You can just buy one instead of having to order parts and build it yourself
- It’s a community project, not a personal project, which means
- more people with the same hardware/software to support one another
- it’s still maintained, and it has long term support
- it’s being developed further (the new model, plans to support heat pumps, etc.)
I should also note that just because the stock image uses OpenHAB doesn’t mean that one has to run OpenHAB. I’ve seen at least two people who have swapped out OpenHAB entirely for something of their own creation. So it’s not just hypothetically possible to run alternative software, there are people already doing it in practice.
I don’t have time to personally make alternative images, but I’d be happy to see more of them, especially if the creator offers the same long term support that the official image has.
