[chendragon]

This type of scenario shouldn't require "smart" home hardware - Traditionally situations like this were addressed by wired/wireless SCADA networks or BACnet or similar protocols.

The only issue is that these things are typically designed to be engineered along with the systems they control, and are difficult for the average user to implement or use.

[toast0]

The thing is, "smart" home hardware is a lot less expensive and more accessible than SCADA or BACnet. I can go out and buy any number of home thermostats, and some of them are even capable of properly supporting all the functions; unfortunately I ended up with the Nest, because it has the best support for enabling both auxiliary heat and emergency heat; but it doesn't have support for interfacing via LAN, and Google rescinded the APIs. Also, the physical interface is infuriating, but it's better than the awful honeywell touchscreen garbage the previous homeowner had installed.