A programmable digital thermostat is one of the simplest ways to reduce energy use. You can save up to 20 percent in heating costs just by lowering your thermostat 5 degrees at night and 10 degrees during the day if no one is home. Similar savings apply to cooling too.
A programmable thermostat will do this automatically. It doesn't make mistakes, and it doesn't forget. Depending on the model, a programmable thermostat can be set to run your furnace and air-conditioning at several settings throughout the day, and the settings can vary from day to day. A heat program, for example, might set the heat at 65 degrees 30 minutes before you wake up and turn it back down to 55 when you leave for work. The setting could go up just before you come home and drop to 60 at bedtime.
A programmable thermostat is easy to use and install. Be sure the power is off when working on a thermostat.
About 15 minutes
Screwdriver, drill, hammer
Stripping wire, drilling holes
Disconnect the wires. The wires are usually color coded, with some of the wires controlling the cooling system (if any) and the others controlling the heat. If the wires aren't color coded, label them with tape, marking the tape with the letter of the terminal the wire attaches to.