The universal Aprilaire® Model 8466 Thermostat is a programmable thermostat that allows you to create personalized programs based on your lifestyle. This enables you to control your heating and cooling system for total comfort and efficiency. The simple addition of a Model 8466 programmable thermostat offers - Energy savings - Set back the temperature overnight and when you're away. According to the U.S. Environmental Protection Agency, a programmable thermostat can save you up to 30% on energy costs annually. Progressive recovery - This feature ensures your home is always at your desired temperature by activating the heating and cooling equipment prior to a scheduled setting; so your desired temperature is assured just when you want it.