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How To Easily Install Nest Thermostat Without A C-Wire

Last Updated Jul 13, 2022

Google Nest thermostats are a great device to install in your home to upgrade it into the new smart home world. It will help you maintain the environment in your home more easily, but what if you don’t have a C-wire to connect to?

You will find that you can install a Nest thermostat in less than an hour without that pesky C-wire. It could be hundreds of dollars to put in that wire and sometimes it is just easier to install it without one. Here is everything you need to know.

How To Easily Install Nest Thermostat Without A C-Wire

A Google Nest thermostat can be installed without a C-wire but you will have to invest in a C-wire adapter. Spending a little money on this will save you hundreds of dollars compared to an HVAC specialist that will have to install a C-wire.

Once you have the adapter and a few tools, you can install the adapter yourself. You do not have to be a specialist or an electrician to complete all the steps. It only takes a few minutes and you will find that it just takes astute reading skills to follow the directions.

Here are the steps to install your new advanced thermostat:

  • Get all the necessary tools gathered.
  • Check the Google Nest’s terminals.
  • Connect the thermals to the proper spots.
  • Connect the C-wire adapter to the device.
  • Put the thermostat on base.
  • Power it on to test drive it.

Get Your Tools

Before you begin the process, gather all the tools you will need. This will make it easier on you so that you can just get everything done in one sweep and not worry about searching during the installation.

Here are all the tools that you will need for a smooth process:

Once you have all this ready, you can begin the process to install your Google Nest thermostat.

Check The Google Nest’s Terminals

You will first need to unscrew the thermostat’s display from the base to expose the terminals. These terminals are necessary to power your thermostat and send messages from the furnace and air conditioner.

It should look like the following:

  • C terminal: used for the c-wire.
  • Rh terminal: Used to draw power for the thermostat.
  • G terminal: controls the fan of your system.
  • Y1 terminal: controls the cooling loop.
  • W1 terminal: controls the heating loop.

Connect The Terminals

Once you have located all the terminals, you are ready to connect the wires to your device. Before you do any connecting, ensure you have turned off the electricity to your HVAC system. You don’t want to electrocute yourself, and you don’t want to fry your thermostat before it is installed.

If you have an old thermostat still in place, remove it from the wires. Keep in mind where each wire is connected, so don’t cross wires into the wrong terminal. Crossing wires can cause everything to go haywire or ruin your thermostat.

You should be able just to insert the wires into each terminal. You can use wire cutters to shorten the wires if need be, but this is optional.

Connect The C-Wire Adapter

Next, you will want to insert the C-wire adapter wires. This will be a little different since you don’t have a C-wire to connect to your thermostat. Take the two wires from the adapter and insert one into the Rh terminal for power. Then take the second wire and put it in the C terminal.

Put Thermostat On The Base

Once all the terminals are in the correct terminals, you are ready to put the thermostat back on its base. Ensure that it is put on right so that it doesn’t fall off and break. Once you have done this, you can return the power to the base and plug in the C-wire adapter.

Turn It On

Now it’s time to test your handy work. Turn on your thermostat and see if everything is working properly. If you have issues, try troubleshooting them. You will have to connect it to the router for it to work correctly.

Risks Of Installing Without A C-Wire

Although you can have your Nest thermostat without a C-wire, there are some complications that come with not using one. You will find that overtime your thermostat may not work appropriately.

Some problems that may arise are that it may cause your house to either become too hot or too cold. You can come home from work and feel like you are entering a sauna. Or you could come home to a freezer.

The second issue is that you may come home to find your thermostat with a blank display. This could be because the battery is dead from not recharging or it could be that the device has expired. This usually happens sooner on devices without a C-wire than devices with.


You don’t need a specialist to install your Google Nest thermostat, and you don’t need a C-wire. It is advised to have one, but you can easily find adapters that can replace this function with all the tools and devices today. You won’t need to spend hundreds of dollars inserting a pesky C-wire.