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 24V HVAC systems (like conventional force air, heat pump, radiant boilers, etc). It does not work with 110-240V HVAC systems (like electric baseboard heat). Smart Thermostats require a C-wire (most homes have one) 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.