Wyze Thermostat C Wire

Does the thermostat require a C wire? If so, is there a conversion harness in planning or is it compatible with another existing harness?

Adding a C wire to a thermostat is not specific to the thermostat brand in general. The process is pretty generic. I have added C wires for Nest, Ecobee, Honeywell and a half dozen others. The process is the same for all.


I’m interested in this too. I currently use a Filitrete Radio Thermostat and have a wall wart wires into the thermostat where the C wire goes.

Neither and electrician or the guy who installed my new boiler new what a C wire was.

Will I be able to use a wall wart with the Wyze thermostat?

Or for people in the know would posting a pic of my boiler panel help tell me if I can run a c wire?


A wall wart or adding a C wire should both work depending on the age of your equipment.

I can understand an electrician possibly not understanding what a C wire is. (Not all electricians work with low voltage systems). But every HVAC company should know. I recommend calling around as it should be easy to find an HVAC company that can do the work.

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It looks like Wyze has already started publishing some info for the thermostat. And once it is opened up for pre-sale next week, there will be more details available.

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a C wire is not required for the Wyze tstat…I’m not sure how much info can be shared since it’s not yet available to order, but as mvb said there should be lots more info when the product page is available next week.


As @Ken.S stated, there is indeed an alternative for people not running a C wire.

More info will be released by Wyze officially
soon I believe so as there will be no speculation or false interpretation through anyone not speaking directly for Wyze.


Well until then, anyone that decides to use a C wire, they are easy to add if you need one! :slightly_smiling_face:


Preorders for the thermostat are open but no install-info is posted. I wish they had put up the installation and technical guide so I would know if it will work with my system.

It does make it a little harder. I would think you could use say an Ecobee for a guide as to what systems it will work with. Most current IoT thermostats seem to work with the same subsets. Of course it may not be an exact match so to be safe I would wait for the full release.

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Install info and a lot of other information and YouTube videos are posted. The information should be required reading: https://wyze.com/thermostat-compatibility

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If you don’t have a C wire, they include an adapter that is installed on the furnace control board.

Or you can add a C Wire as shown above. Lots of options.

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My existing AC thermostat (Trane) does not have a C wire at all. Only G,R,W, and Y. So my question is: Do I need to add a C wire in order for the WYZE thermostat to work, or not? WYZE has this installation video on YouTube that mentions this C wire and using an adapter to add one, etc. However, the video does not make it clear as to whether or not a C wire is required in order for the thermostat to work. Thanks in advance for your responses!

Yes the C wire is required. It is what supplies power to the thermostat as it does not use batteries I believe.

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Thanks! As I mentioned, the video does not state this, nor does it give any instruction about fishing the wire through the wall which I will have to do once my thermostat arrives.

Fishing wire through walls is well beyond the scope of installation videos. Too many variations to even begin to cover.

That said a search on YouTube for “Adding a C wire” will bring you to many videos showing a variety of installs in a variety of circumstances.

In essence a C wire is a C wire. They are exactly the same for Wyze, Nest, Ecobee, Honeywell etc.

I am going to have to disagree with @rbruceporter on this point.

A C-wire is NOT required. Wyze provides a C-wire adapter for systems where a C-wire was not run from the furnace to the thermostat. There is no need to fish a wire from the furnace. A number of testers successfully used the adapter.

The installation video (https://youtu.be/kPieIgLOhFg) gives pretty clear instructions on installing the adapter. They begin at about 2:15 into the video.

In essence, the adapter jumps the C-wire terminal on the main control board on the furnace with one of the other wires to provide the power for the Wyze thermostat. I had a C-wire, so I didn’t need to use the adapter. So I don’t know which wires are jumped together.


@mvb took my answer. well played.

Ok let me rephrase to be clearer. You need to provide power either with an actual C wire or via using either a physical C wire you either have or add. OR you can repurpose the fan wire which is what the C wire adapter WYZE provides does.

No matter which path you choose you are providing power via a “C” wire at the Thermostat. So I will stand by what I said. Yes, you need a C wire. Either an actual wire or a repurposed wire via the Adapter provided. But however you bring power to the thermostat you MUST do so or the thermostat will not work.

The downside of the adapter is the fan controller is now tied to the AC and Heat and can not be run independently. Only when one or the other is on.

Again NONE of this is unique to Wyze. The exact same Adapters or C wire requirements exist for Ecobee, Nest, Honeywell etc.