Installation

Do I need a c‑wire?

If you're wondering what a c-wire is or how to look for one, you’ve come to the right place. Our step-by-step videos will guide you through the process and answer all your questions.

For Sensi smart thermostat or Sensi Lite smart thermostat, a common wire (c-wire) is required for heat only systems, cool only and heat pump systems.

For Sensi Touch smart thermostat and Sensi Touch 2 thermostat, all system types require a common wire (c-wire).

C-wire help made simple.

Start with the first video and follow along in order until you find the solution that’s right for you.

Basic c-wire introduction

Learn about the basics of common wire installation by watching this video. You will also be guided on how-to and when-to connect c-wires to thermostats. It also shows three different scenarios to choose which methods works best for you.

Finding and using an unused wire as a c-wire

Sensi Thermostats require a common wire to complete installation. This video will guide you in checking if you have a common wire, or an unused common wire from your previous thermostat that you can use to install your Sensi Thermostat.

Using the g-wire as a c-wire

If you can't find an unused wire or common wire, you can also use the fan wire or g-wire as a common wire. This video serves as a second option in common wire installation.

Installing Common Wire Maker Kit

If there is not an extra unused wire running from the thermostat to the furnace, and using the g-wire as a common wire is not an option, in most cases, installing a Common Wire Maker Kit is the best solution.