I wish I would have known that if your smart thermostat can’t connect to Wifi it won’t run your AC.
This is HORRIBLE fault tolerance. Reaching out Ecobee to see if their Thermostats operate in a similar fashion. If they don’t I’ll end up replacing both Nest Thermostats.
This type of reliance on Wifi for basic operation is a no no unless there’s no way possible to deliver core functionality.
I have an ecobee – it operates to control the HVAC system when it is not connected to wifi. It is hardwired to the HVAC controller. Without wifi, of course, remote control via the ecobee app does not work.
I get to test this frequently because the ecobee drops the network connection several times a day, for about three minutes, despite sitting 6 feet away from the nearest router. The ecobee suffers from DHCP lease renewal problem.
I’m running an ecobee also. It works fine with no internet connection. All my major home automation devices work fine with no internet - front door lock, garage door opener, security cameras. Ring doorbell still works as a doorbell but can’t do anything else without wifi.
Damn if it wasn’t just the Nest. Our HVAC system is clearly in its twilight years. There was a component that prematurely degraged at the same time the Nest Wifi broke. So I unfairly blamed the Nest. I meant to udate this thread but perhaps out of embarassemt I procrastinated.