Most smart thermostats require a blue "C" wire to provide constant power.
Ecobee Smart Thermostat Premium (includes air quality monitor and remote sensors). buy thermostat
Honeywell Home 7-Day Programmable (reliable, no Wi-Fi needed). 1. Choose Your Type Smart Thermostats Connect to Wi-Fi. Control via smartphone apps. Most smart thermostats require a blue "C" wire
Upgrading your thermostat is one of the most effective ways to lower energy bills and improve home comfort. Quick Summary: Which One Should You Buy? learns your schedule automatically).
Google Nest Learning Thermostat (sleek design, learns your schedule automatically).