Having a thermostat is important in every season, especially in extreme weather. A good thermostat sets the accurate temperature to ensure your comfort. Also, it stores the temperature record at various times of the day. As technology evolved, the thermostat has changed over the years. Now nobody uses a mercury switch thermostat. More Info: https://greenleafair.com/manual-smart-or-programmable-thermostat-which-one-is-better/