You might be wondering exactly what a C-wire is and how it works. Don’t worry. We will go over all the details in this article. We will also discuss whether you need to buy a C-adaptor or not.
You might be wondering why most smart thermostats or smart devices, in general, don’t use batteries. Trying to maintain a connection to your thermostat would easily drain batteries within a few days.
If you were constantly having to change the batteries in the thermostat, this would probably actually make your life harder rather than easier.
Here are some additional reasons why it would be hard for a smart thermostat to run on batteries:
- Smart thermostats are connected to WIFI which requires a lot of power. Smart thermostats are always on. The large touch screens on the display drain power easily. Batteries can die which means you will not be able to access your thermostat remotely until you change the batteries.
What is a C-Wire?
You might have stumbled across blogs or forums from people saying that they do not use C-wires, or that they did not spend the extra money for a C-wire adaptor. This can be extremely bad for the health of your thermostat. It can also void your warranty if you installed it incorrectly without an adaptor.
A c-wire is an extra power that is put on your thermostat to provide a path for power. The C just stands for common and should be labeled “C” on the back of your thermostat for clear identification.
The C wire allows the thermostat to be powered without interfering with other wires that are on your switchboard. In addition, the C-wire:
- Provides a return path for power so no wires are disrupted Provides constant and stable power to the thermostatImproves WIFI connectivity
Since the thermostat requires WIFI to work and change settings, you always want to make sure you do everything you can to make sure the connection is the best it can be.
How Do I Know If I Need a C-Wire?
Some HVAC systems come with a C-wire, while others do not. You will need to check the wiring in your system before purchasing a thermostat.
Here are some steps you can take to see if you already have a C-wire:
- Take the current thermostat off the wall to see the wiring behind it. You should see different colored wires connected to letters. If you have a wire going into a terminal labeled “C,” then you have a C-wire. If the terminal labeled “C,” is empty, you probably will need to buy a C-wire adaptor.
Sometimes the HVAC company might have not hooked up the wire though. Make sure to check for extra wires hanging around that are not connected to anything. You can also check the control board and see if there is a C terminal there with a wire.
If you are still in doubt, you can call someone from your local HVAC company and have them check for you. They will be able to tell you for sure if there is a C-wire or not.
Connecting the C-Wire Adaptor
Now that you know if you need a C-wire for your smart thermostat, you may be wondering how to connect it.
If you have determined that you do not have a C-wire and bought the option with the adaptor, connecting is easy:
- Remove the wire at the G terminal and connect it to the C terminal. Remove the wire at the Y1 terminal and pair it together with the blue wire. Close the pair together with the caps that come with the adaptor kit. Connect the green wire to the G terminal and the yellow wire to the Y1 terminal.
Your C-wire should not be connected to the thermostat and be ready to power your thermostat.
