Emerson Sensi Wi-Fi Smart Thermostat for Smart HomeFrom across the room or across the country, your Sensi Wi Fi thermostat makes it easy to remotely control and schedule your home comfort Anytime. Anywhere. Sensi thermostat does not require a common wire (c wire) for most installations, so it is compatible with the HVAC equipment in many homes in U. S. & Canada. A c wire is required for heat only, cool only and heat pump (without aux) systems, and for use with Apple HomeKit. Check to make sure it will