I'm very interested in this— I have a fairly new Vitodens 100 boiler + Ecobee and also a heat pump system with its own thermostat, and I'm frustrated by several elements of this setup:

- The Vitodens has like ten stages, but the Ecobee has no way to command them, it's just a binary call to the Taco pump for heat / no heat, with the boiler deciding on its own how hard to push (I guess based on the outside air sensor and maybe time of day?)

- The Vitodens is monitoring the return boiler water temperature, but the Ecobee doesn't know anything about that.

- None of this is interlinked with the heat pump, so the systems can run on top of each other and end up with the wrong parts of the house overheated or left cold. The heat pump's controller is proprietary but it works with the NetHome Plus app so there is a bridge to get the units on homeassistant.

I don't have the spoons right now to try to beat this all into shape, but eventually I'd like to get HA temp monitors in multiple places in the house so that a single central system can make smarter decisions about which system to run and when. For example, in the evening I mostly care about the bedrooms, and the bedrooms are covered by zone 2 of the heat pump, so it would make sense to prioritize the heat pump then and only run the boiler if the heat pump isn't able to keep up; whereas in the daytime if heat is needed, it's probably throughout the house so the boiler should run.