![Emerson Sensi 7-day Programmable Wi-Fi Smart Thermostat, No C-Wire Required for Most Systems ST55 - The Home Depot Emerson Sensi 7-day Programmable Wi-Fi Smart Thermostat, No C-Wire Required for Most Systems ST55 - The Home Depot](https://images.thdstatic.com/productImages/27c4905e-cdfc-48c6-9efd-8b1077091e04/svn/white-emerson-programmable-thermostats-st55-66_600.jpg)
Emerson Sensi 7-day Programmable Wi-Fi Smart Thermostat, No C-Wire Required for Most Systems ST55 - The Home Depot
![MoesGo Programmable WiFi Smart Thermostat for Home, No C-Wire Required by C- Wire Adapter, with Zone Remote Sensor, Remote Control Tuya/Smart Life, Compatible with Alexa and Google Assistant, 24VAC - Amazon.com MoesGo Programmable WiFi Smart Thermostat for Home, No C-Wire Required by C- Wire Adapter, with Zone Remote Sensor, Remote Control Tuya/Smart Life, Compatible with Alexa and Google Assistant, 24VAC - Amazon.com](https://m.media-amazon.com/images/I/61k3DaUTqbL._AC_UF894,1000_QL80_.jpg)
MoesGo Programmable WiFi Smart Thermostat for Home, No C-Wire Required by C- Wire Adapter, with Zone Remote Sensor, Remote Control Tuya/Smart Life, Compatible with Alexa and Google Assistant, 24VAC - Amazon.com
![Emerson Sensi 7-day Programmable Wi-Fi Smart Thermostat, No C-Wire Required for Most Systems ST55 - The Home Depot Emerson Sensi 7-day Programmable Wi-Fi Smart Thermostat, No C-Wire Required for Most Systems ST55 - The Home Depot](https://images.thdstatic.com/productImages/8da7df3a-222e-4de5-b8dc-012d9e691939/svn/white-emerson-programmable-thermostats-st55-64_1000.jpg)
Emerson Sensi 7-day Programmable Wi-Fi Smart Thermostat, No C-Wire Required for Most Systems ST55 - The Home Depot
![Emerson Sensi 7-day Programmable Wi-Fi Smart Thermostat, No C-Wire Required for Most Systems ST55 - The Home Depot Emerson Sensi 7-day Programmable Wi-Fi Smart Thermostat, No C-Wire Required for Most Systems ST55 - The Home Depot](https://images.thdstatic.com/productImages/cc88d87a-35f6-4151-8df2-5fcc22a02df9/svn/white-emerson-programmable-thermostats-st55-1f_600.jpg)
Emerson Sensi 7-day Programmable Wi-Fi Smart Thermostat, No C-Wire Required for Most Systems ST55 - The Home Depot
![Does anyone know I can install a smart thermostat without additional wiring? How can I tell if the blue wire is the C wire? It's an air handler for a/c only. : Does anyone know I can install a smart thermostat without additional wiring? How can I tell if the blue wire is the C wire? It's an air handler for a/c only. :](https://preview.redd.it/x4o2gcbyfym91.jpg?width=640&crop=smart&auto=webp&s=31429b7c9e94f8a7ccdf5cba3a8bf9bc94e7629e)
Does anyone know I can install a smart thermostat without additional wiring? How can I tell if the blue wire is the C wire? It's an air handler for a/c only. :
![Advice on how to wire a 4 wire RGWY wifi thermostat to an old hvac with no c wire? - Home Improvement Stack Exchange Advice on how to wire a 4 wire RGWY wifi thermostat to an old hvac with no c wire? - Home Improvement Stack Exchange](https://i.stack.imgur.com/j5dG1.jpg)