Does my Sensi thermostat need a common wire, or "c-wire"?

The need for a common wire, or “c-wire,” depends on which Sensi thermostat model you have and your system type.

The Sensi smart and Sensi Lite smart thermostats work on most conventional heating and cooling systems without a c-wire. However, you will need a c-wire for:

• heat only systems
• cool only systems
• heat pump systems

Apple HomeKit Compatibility

The Sensi Touch smart and Touch 2 thermostat always require a c-wire.

Reference the master compatibility chart in this article to review c-wire needs.