emerson sensi touch wi-fi smart thermostat with touchscreen color display, works with alexa, energy star certified, c-wire required, st75 black 5.625" x 3.4" x 1.17" emerson the sensi touch wi-fi smart thermostat puts comfort control at your fingertips whether you are at home or on-the-go. just a tap of the easy-to-use touchscreen display or free mobile app lets you remotely access, change or program your home temperatures – anytime. anywhere. designed to work with hvac equipment in most homes* (u.s. & canada only), sensi guides you through each step of the diy installation process with proven, in-app instructions. a common wire (c-wire) is required for all system types. refer to our online compatibility resources at sensicomfort.com/compatibility to make sure sensi thermostat will work in your home. once your sensi thermostat is up and running, you can let your location automatically adjust your temperature settings with geofencing, or use the intuitive controls to create a custom schedule to fit your lifestyle and save money on hvac related energy costs.