I am interested in replacing an older thermostat with a modern networked 'smart' thermostat \ humidity monitor. That being said, does the photographed thermostat have a C-wire?
The thermostat controls an air conditioner in a Florida storage facility. Fortunately, the AC handler is proximal to the thermostat controller
As I understand it, the common wire is often necessary to provide a return path, one of two wires necessary to power the electronics in a smart thermostat.
UPDATE: upper thermostat panel removed. Blue wire not connected:
If there is 24V AC between the RED and BLUE wire, is it reasonable to conclude that the BLUE wire is the 'C Wire' required for smart thermostats?