Our house has a commercial style HVAC system. The controllers for everything (relays) are very simple. The run on a protocol called BACNet that is unauthenticated and pretty straightforward.
I was able to read in all the data points and then use the weather forecast and a few other data points to make changes to my HVAC system. The comfort different has been very drastic. Our house doesn't overheat on hot days and doesn't get cold fast when the temperature drops. (I am in the Northeast where there are big swings).
Hey, I apologize You were exposed to BACNet. Seriously. That was one the worst HVAC protocols I've dealt with. It seemed (1990's) to do most stuff in obtuse ways compared to other HVAC comms.
At least The standards were supported (eg. 4-20mA).
I was able to read in all the data points and then use the weather forecast and a few other data points to make changes to my HVAC system. The comfort different has been very drastic. Our house doesn't overheat on hot days and doesn't get cold fast when the temperature drops. (I am in the Northeast where there are big swings).