Sensi SupportTouch Wi-Fi ThermostatBefore you buy › How can I be sure a Sensi thermostat will work with my HVAC system?

Before you buy

How can I be sure a Sensi thermostat will work with my HVAC system?

Sensi thermostats work with most combined heating and cooling systems, however, the need for a common wire or “c-wire” is different based on the Sensi thermostat model. Please see the chart below for full compatibility information.

Sensi master compatibility chart

Combined Heating and Cooling Systems

The Sensi Wi-Fi Programmable Thermostat works on most combined heating and cooling systems without a common wire, or “c-wire.”

The Sensi Wi-Fi Thermostat also works on most combined heating and cooling systems without a c-wire, however, will require a c-wire for Apple HomeKit functionality.

The Sensi Touch Wi-Fi Thermostat always requires a c-wire.

Heat-only or Cool-only Systems

On heat-only or cool-only systems, Sensi thermostats require a c-wire. A heat-only or cool-only system without a c-wire installed will cause the Wi-Fi connection to drop out after about two hours of operation.

The Sensi Touch Wi-Fi Thermostat requires a common wire for basic operation.

If you need a c-wire, there are a few main options:

  • Using an extra, unused wire as a c-wire
  • Using your thermostat’s g-wire (fan wire) as a c-wire
  • Installing an Emerson Thermostat Common Wire Kit

If you would like to understand what a c-wire is and learn more about these three options, watch our helpful videos on our c-wire page.

One of these three options work on most HVAC systems, however, if you have a 2-wire, heat-only system, you will need to run a new wire from your furnace to your thermostat or install a 24VAC power transformer to supply constant power to your Sensi thermostat.

Incompatible system types include:

  • Line Voltage Systems (generally 110V/220V baseboard heating)
  • Systems with remote sensors - While the Sensi thermostat may be compatible with this system type, it will not be able to gather data from existing remote sensors
  • Proprietary or Communicating Systems - The Sensi thermostat can’t communicate with serial protocols, although some proprietary HVAC equipment can be wired with standard HVAC wires

Additionally, the Sensi thermostat do not control whole home humidifiers or dehumidifiers.

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