Weekday/Weekend Programming – One program for the weekdays and a separate program for the weekends with 4 program periods per day. Energy Savings – Program to save up to 33 percent on annual heating and cooling costs (if used as directed, savings may vary depending on geographic region and usage). Easy to Use – Basic operation keeps programming simple. Backlit Display – Easy to read even in dimly lit rooms and hallways. Early Start Function – Adjusts the pre-heating/cooling of your home so you are comfortable at your programmed times. Filter Change Reminder. Works with heating and cooling systems. Does not work with heat pump systems and electric baseboard heat (120-240V). 1-Year Warranty.