Here are common uses for wire colors: Blue or Black – C – Common wire, may be unused by your existing thermostat. Red – R – 24VAC power from the furnace’s transformer. Red – Rc – 24VAC (dedicated to heat call) Red – Rc – 24VAC (dedicated to cooling call) Green – G – Fan. White – W – Heat. Yellow – Y – Air conditioner. The thermostat wire is color coded so the technician can identity which wire goes to which port on . Read reviews and find the best prices on Amazon.com. The great powers of Tony Fadell’s Nest Learning Thermostat seemed so magical. . However, the colors of the wires do not necessarily mean anything, it just . Two smart thermostats that do not require a C Wire: ecobee3 (our favorite) or . If you plan on getting a smart thermostat and don’t have a c-wire, please save yourself . Installation requires a screwdriver and the ability to read a wiring diagram. . Using a c-wire is the best way to provide the constant power that is required. Find out how to install your new Wi-Fi thermostat without C wire, and learn more . type of job, you can but a spool of color-coded thermostat wire and go to town. . process and are ready to pick the best wifi thermostats that require a c wire. Thermostat C-Wire provides power current for smart thermostat devices. . Sometimes wire color might not match that scheme described above. It’s also an “excellent” way to disable the manual setting on your house fan, so no one should . In most cases, Nest thermostats can charge their built-in battery using your system’s heating and cooling wires. But in a small number of situations you may need . 14 thg 1, 2016 – The C, or “common” wire can make — or break — your thermostat installation. . Same great Nest, now with even better looks · These smart thermostats . though, with power-hungry Wi-Fi connections and full-color screens, . 24 thg 10, 2017 – Buying a thermostat that needs C wire? Not sure whether your HVAC system has the Common wire? The best thing to do if there is no C-Wire is .