![How to Install Ecobee3 Lite Smart Thermostat || Without C Wire || Upgrading My Thermostats - YouTube How to Install Ecobee3 Lite Smart Thermostat || Without C Wire || Upgrading My Thermostats - YouTube](https://i.ytimg.com/vi/FCQjfsIGtME/maxresdefault.jpg)
How to Install Ecobee3 Lite Smart Thermostat || Without C Wire || Upgrading My Thermostats - YouTube
![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://cf-images.us-east-1.prod.boltdns.net/v1/jit/1834613806001/be7891c1-bbb0-4ba3-b0b7-1071cf8ab7f9/main/1280x720/47s232ms/match/image.jpg?pubId=66036796001)
Google Nest Power Connector - C-Wire Substitute - Compatible with Nest thermostats GA02493-US - The Home Depot
![Thermostats 24 Volt Transformer C Wire Power Adapter for Nest, Ecobee, Honeywell WiFi Thermostats, Power Supply for Nest Hello, Ring Smart Doorbells Chime - Amazon.com Thermostats 24 Volt Transformer C Wire Power Adapter for Nest, Ecobee, Honeywell WiFi Thermostats, Power Supply for Nest Hello, Ring Smart Doorbells Chime - Amazon.com](https://m.media-amazon.com/images/W/MEDIAX_792452-T2/images/I/71qO0x7bNcL.jpg)
Thermostats 24 Volt Transformer C Wire Power Adapter for Nest, Ecobee, Honeywell WiFi Thermostats, Power Supply for Nest Hello, Ring Smart Doorbells Chime - Amazon.com
![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
![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. :
![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
![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)