A simple; easy to use 5-2 day programmable thermostat. A programmable thermostat can save you up to 33-percent off your energy bill; if used as directed. You set it up to adjust the temperature when you are away or asleep-times when you don't necessarily need to heat or cool your home to optimum comfort-and your HVAC equipment runs less. Plus; your heating or cooling comes back to the comfort level you desire before you come home or wake up. Honeywell programmable thermostats are easy to install and are pre-programmed for your convenience. For more than a century; Honeywell thermostats have been the popular choice of homeowners. This thermostat is compatible with single-stage heating/cooling systems; heating; cooling; heat pumps without backup heat; mill volt; pellet stoves and fireplaces. It does not work with electric baseboard heat (120-240 V); heat pump systems with backup heat or multi-stage heating/cooling.