From the Manufacturer
Maximize comfort, reduce household energy use, and save money with the RTH6450D 5-1-1 Programmable Thermostat from Honeywell. Featuring a user-friendly design that lets you program weekdays, Saturdays, and Sundays separately, this thermostat makes it easy to sync your home's heating and cooling system with your schedule, and it is Energy Star rated for efficiency you can count on. Programmable 5 1 1 day with 4 program periods per day. For heating and air conditioning systems. Large backlit display with menu driven programming. Soft key controls. Shows room and set temperature. Exclusive Smart Response technology. Compatible with most electric, gas oil single stage furnaces; heat pumps without backup heat; heat only, and cool only furnaces. Will not work on electric baseboard heat. Precise temperature control + 1 F. Automatically switches from heat to cool to adjust the preheating cooling of your home so you can feel comfortable at your programmed times. Battery powered. Approximate size: 3.75'' H. x 6'' W. x 1.25 W. Off white. ENERGY STAR rated.