![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. :
![electrical - Where should I connect the C wire in a Janitrol furnace? - Home Improvement Stack Exchange electrical - Where should I connect the C wire in a Janitrol furnace? - Home Improvement Stack Exchange](https://i.stack.imgur.com/pEsK8.jpg)
electrical - Where should I connect the C wire in a Janitrol furnace? - Home Improvement Stack Exchange
![Programmable Wifi Smart Thermostat , No C-wire Required By C-wire Adapter, With Zone Remote Sensor | Fruugo SK Programmable Wifi Smart Thermostat , No C-wire Required By C-wire Adapter, With Zone Remote Sensor | Fruugo SK](https://img.fruugo.com/product/6/33/647250336_max.jpg)
Programmable Wifi Smart Thermostat , No C-wire Required By C-wire Adapter, With Zone Remote Sensor | Fruugo SK
![Google Nest Power Connector - C-Wire Substitute - Compatible with Nest thermostats GA02493-US - The Home Depot Google Nest Power Connector - C-Wire Substitute - Compatible with Nest thermostats GA02493-US - The Home Depot](https://images.thdstatic.com/productImages/b2d9413f-eccf-4580-8885-a2b4a4ba1f5f/svn/white-google-smart-thermostats-ga02493-us-4f_600.jpg)
Google Nest Power Connector - C-Wire Substitute - Compatible with Nest thermostats GA02493-US - The Home Depot
![Honeywell home ventilation system with no c wire for thermostat. How can I substitute the g for the c without blowing a fuse? - Home Improvement Stack Exchange Honeywell home ventilation system with no c wire for thermostat. How can I substitute the g for the c without blowing a fuse? - Home Improvement Stack Exchange](https://i.stack.imgur.com/nqLQO.jpg)
Honeywell home ventilation system with no c wire for thermostat. How can I substitute the g for the c without blowing a fuse? - Home Improvement Stack Exchange
![Emerson, Sensi 7-day Programmable Wi-Fi Smart Thermostat, No C-Wire Required – St. John's Institute (Hua Ming) Emerson, Sensi 7-day Programmable Wi-Fi Smart Thermostat, No C-Wire Required – St. John's Institute (Hua Ming)](https://i.ebayimg.com/images/g/uF8AAOSwOZRk5OLP/s-l1600.jpg)
Emerson, Sensi 7-day Programmable Wi-Fi Smart Thermostat, No C-Wire Required – St. John's Institute (Hua Ming)
![915 Generation Programmable WiFi Smart Thermostat No C-Wire Required By C- Wire Adapter with Zone Remote Sensor 24VAC | Jumia Nigeria 915 Generation Programmable WiFi Smart Thermostat No C-Wire Required By C- Wire Adapter with Zone Remote Sensor 24VAC | Jumia Nigeria](https://ng.jumia.is/unsafe/fit-in/500x500/filters:fill(white)/product/93/7740652/1.jpg?0363)
915 Generation Programmable WiFi Smart Thermostat No C-Wire Required By C- Wire Adapter with Zone Remote Sensor 24VAC | Jumia Nigeria
![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)