Since they are all HomeKit all that sensor and state data is shared with all other HomeKit devices. So I created a HomeKit Automation that triggers the start of the window A/C units when temp triggers a certain threshold and during a certain time of day. Similar trigger to turn the AC off.
But you can just pick up a standalone sensor like: https://www.apple.com/shop/product/HL232LL/A/ihome-control-i...
For the two dumb window AC units, I plugged them into a HomeKit smart plug like: https://www.apple.com/shop/product/HKEH2VC/A/elgato-eve-ener... With that plug you also get actual energy use and cost in real-time/historical as well.
Since they are all HomeKit all that sensor and state data is shared with all other HomeKit devices. So I created a HomeKit Automation that triggers the start of the window A/C units when temp triggers a certain threshold and during a certain time of day. Similar trigger to turn the AC off.
I found this HomeKit app to offer much more fine grained automation rules: https://itunes.apple.com/us/app/home-smart-home-automation/i...