Winter or summer, a programmable thermostat keeps your home temperature on a schedule that maximizes both efficiency and comfort. Are you typically gone all day but want the home toasty when you return? Just teach your thermostat to do it for you. By setting the temperature back 10% to 15% for 8 hours when no one is home, you can save as much as $150 a year. If every house in America did this it would drop our total greenhouse gas production by about 35 million tons of CO2.

Programmable thermostats typically pay for themselves within a year. Some are more powerful than others, but all ENERGY STAR programmable thermostats now include four default program periods per day, allowing you to adjust to typical household rhythms: Sleeping, start-of-the day, away at work or school, and afternoon/evening.

To choose the right model when you're at the hardware store or superstore, consider your schedule. Programmable thermostats come in 3 modes:

  • 7 days, where each day is different.
  • 5-2, where Monday through Friday is the same, and Saturday/Sunday is the same.
  • 5-1-1, where Monday through Friday is the same, and Saturday & Sunday are different.

Other ways the programmable thermostat is useful:

  • If you travel a lot, look for a model with vacation override.
  • Some will also remind you to change your heating system air filter.
  • A keyboard lock can rout out household sabotage by your children-unless you rely on your teenager to program all home electronics (you shouldn't need to for this).

Unless you're replacing an old unit or are confident in your DIY skills around the house, have a professional do the installation. Schedule it along with a tune-up of your heating or cooling system. Even if you have someone else install it, you can buy it yourself. Ask a store associate to point you to the thermostats.

Once you have the thermostat installed, programming is easy. The instruction manual will walk you through each period of the day for the different types of days. Most models use arrow buttons to increase or decrease the temperature and another button to move to the next period. For those at home most of the time a programmable thermostat offers more limited benefits, but still takes out the human error. It's also good for enforcing a little thermal discipline. If you're trying to moderate your heating and cooling demands, use the programmable thermostat to slowly change your habits. Remember, you can save as much as $150 on your utility bill by making changes to your thermostat.