So I got a buderus #heatpump and the mobile app is _quite_ limited, also not possible to access data via any open protocol 🙄

So I bought an ems-esp gateway from https://bbqkees-electronics.nl.
It gets power via the bus connection (3,5mm jack, _one_ cable), then I just had to set up the network connection and #mqtt to make everything appear in #homeassistant.

Mind blown, best experience for quite some time.
And you can make it only read from the bus, so no worries to misconfigure something.