So, CalDav… Right now I’m going to use my Google Calendar because I need to tackle CalDav before I tackle OwnCloud 
So, I’d implement something like your “Calculate the type of day” Rule based on my workdays/holidays. Relatively straightforward. With Google, there are holidays calendars one can subscribe to. They are read only. Could CalDav play a part with the Holidays Calendar to trigger setting the type of day?
I can create a separate “openHAB” calendar in my Google Calendar. I can add my HVAC schedule there using weekly repeating entries for each time window.
I am having a hard time understanding how to make use use of the binding(s). I can’t conceptualize the difference between these:
CalDAV Command
- Used to execute commands through an event, triggered at the start or the end of an event.
CalDAV Personal
- Used to detect presence through calendar events.
- Used to show upcoming/active events in openhab.
Mike