Typically, when you purchase a new thermostat, you'll have to supply your own batteries. However, The Home Depot carries 4 smart thermostat options that have batteries included so a separate purchase isn't necessary.
Can you replace a regular thermostat with a smart thermostat?
In most cases, you can use your existing thermostat hook-up for a newer, smarter thermostat. Installing your new thermostat usually only takes about 30 minutes. Most smart thermostats include step-by-step setup instructions to make installation a smooth process.