In order to power most of our Wi-Fi smart thermostats, your system must contain a C-wire. Use the wiring compatibility tool below or see additional support content to confirm that your system meets the compatibility requirements. This will determine compatibility with most systems, but as wiring systems vary from home to home, there may be some exceptions.
There is an exception, specifically if you have the Round Smart Thermostat (previously known as the Lyric Round Wi-Fi Thermostat). That can be used without a C-wire in most instances. However, if you plan to link the Smart Round Thermostat to an Apple HomeKit hub, have forced air zone panel or a Taco zone value, the C-wire is required.
1. Does your current thermostat have 110V or higher written on it?
2. Do you have thick wires that are connected using wire nuts?
3. Do you have a wire connected to terminal labeled "C"?
4. Do you have an extra wire that is not connected to any terminal on the thermostat wall plate?
5. Do you have a wire connected to terminal labeled "G"?
Still need help? Let us answer your question.
Call our dedicated support staff at 1-855-733-5465, M-F 9 AM – 8 PM CSAT, Sat-Sun 9 AM – 5 PM CST.
Please ensure you have the following information available before you call so our staff can help you more accurately:
The type of system in your home, for example: Furnace, Boiler, Heat Pump, Electric Base Board, etc.
Make and model of current thermostat.
Take the face plate off of your current thermostat and record the color and designated letter/number on the wire terminal.