Amazon Smart Thermostat is ENERGY STAR certified. Easily switch your traditional thermostat and help reduce energy usage. For on-the-go comfort, let Alexa set the temperature, or set it yourself from anywhere with the Alexa app. Amazon Smart Thermostat is compatible with most 24-Volt HVAC systems (like conventional force air, heat pump, radiant boilers, etc.). It does not work with 110 - 240-Volt HVAC systems (like electric baseboard heat). Smart thermostats require a C-wire (most homes have1) or a C-wire adapter kit (sold separately). Guided installation instructions are included in the Alexa app and will walk you through checking for a C-wire or options for powering your thermostat. B08J4C8871