Thermostat Wiring Compatibility

Honeywell Wi-Fi Programmable Thermostats

In order to power most of our Honeywell 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 Lyric Round 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?


YES:

Not compatible

NO:

Next Question


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2. Do you have thick wires that are connected using wire nuts?


YES:

Not compatible

NO:

Next Question



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3. Do you have a wire connected to terminal labeled "C"?

YES:

Congratulations, this thermostat will work with your system.

NO:

Next Question

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4. Do you have an extra wire that is not connected to any terminal on the thermostat wall plate?

YES:

Watch the video called:

"Substitute extra wire for C-wire"

NO:

Next Question

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5. Do you have a wire connected to terminal labeled "G"?

YES:

Watch the video called:

"Substitute G-Wire for C-wire"

NO:

Sorry, this Wi-Fi thermostat won't
work with your system. Click here for other thermostat options.

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Still need help? Let us answer your question.

To help you know for sure if your system will work with the Wi-Fi thermostat, please email the following information, as this will better allow us in assisting you with an answer.

  1. Send an email to HCHCustomercare@honeywell.com. Please make sure you include in your message:
    1. Write “Thermostat Wiring Compatibility Question” in the Subject Line
    2. Attach a photo of your current wall plate with wires connected to the lettered terminals
    3. Include your name
    4. Current model number and/or brand of your thermostat
    5. Your new Honeywell Home thermostat model number (i.e. RCHT8612WF, RTH9585WF)
    6. The type of system in your home (i.e. Furnace, Boiler, Heat Pump or Electric Base Board).
  2. After sending the email, please call us at 1-855-733-5465