So what should a building automation system be like?
At one end, its a hobbyist/geek’s world. You build it, program it and install it. At the other, its a system installed (usually when your house/office/building is built) by a specialist company who then spend a huge amount of time setting it up, and then they return to it every time something needs reconfiguring.
What is there in the middle?
There are a large number of specialist systems utilising use of cheap micro-controllers which are designed to cover one specific task pretty much in isolation. Some of these systems even do a good job. Their designers then build their own web-enabled extensions so that you can install their app and visit their website to interact with their heating controller/aircon/solar controller/energy monitor/etc./etc.
Something is needed to glue all these different systems together or replace them. But most importantly, any system system must be able to be operated (and configured) by the user. If your partner/wife/mum can’t work it, it’s pointless.