To have your thermostat automatically go from heating to cooling (auto-changeover), you will need an outdoor sensor. The outdoor sensor will communicate with your thermostat and tell it that it is warm enough outside to stop turning the heat on or that it is cool enough outside to stop turning on the Air Conditioner.
Thermostats such as Honeywell thermostat and White Rodgers thermostats can be found at www.supplyhouse.com
