Old thermostat has wire 1, 2 & 3. Which smart thermostat is compatible? : r/electrical
Older home - heat only - 2 wire : r/smarthome
Wifi Thermostat - DoItYourself.com Community Forums
Trying to replace this old 2 wire thermostat for a newer digital one. Problem is older unit does not have leads labeled or which cable is which. Any help on how to
How To Install A Wifi Thermostat With Out And With C Wire - YouTube
Is your wiring compatible with a smart thermostat? Our guide to low voltage, line voltage, and more – Smart Thermostat Guide
2-Wire Installation for Honeywell Thermostat - YouTube
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
Old thermostat works, but I can't get the Honeywell T9 to work. T9 require C Wire that was not in the wall. I added C wire & RC wire via plug-in 120v
Honeywell THX9421R5021WW 2 Wire IAQ High Definition Touch Screen Thermostat with Red LINK Technology, White: Amazon.com: Tools & Home Improvement
heating - Wifi thermostat to replace old mechanical 2-wire 110V Honeywell? - Home Improvement Stack Exchange