Of all the ways to save energy in your home, using a programmable themostat is one of the easiest ways to save money and help the environment. Nearly half of a home’s annual energy bill costs pay for heating and cooling. By helping to more efficiently time the cooling and heating of your home, properly using a programmable thermostat can have a big impact on this sizable cost — saving up to $180 a year.

Choose the right programmable thermostat:

To decide which model best fits your household, think about your family’s schedule. How often are you away from home? How regular is your schedule? Do you do the same thing every weekend? There are typically three types of thermostats:

7-day models are best if your daily schedule is variable. This model is best if you or other family members come home at different times on different days. This model allows you to set different programs for different days — usually with four possible temperature periods per day

5+2-day models are best if your schedule is the same five days a week, and similar on both weekend days. This model typically uses the same schedule every weekday, and another on weekends.

5-1-1 models are best if you leave the home at different times on Saturday and Sunday. This type of model typically keeps one schedule Monday through Friday and other schedules on Saturdays and Sundays.

Have the thermostat properly installed:

Installing a programmable thermostat is simple, but does require some preparation and consideration:

• Read all instructions carefully.
   
• Shut down your electricity during the installation.
   
• If more than a simple replacement is required, call a certified HVAC profession to ensure a proper installation. Consulting a professional is a good idea if you are making other changes to your heating and cooling system to ensure that you are maximizing your energy savings.
   
• Be sure to install your programmable thermostat unit on an interior wall, away from heating or cooling vents and other sources of heat or drafts  such as doorways, windows, skylights, direct sunlight or bright lamps)
   
• Use the previous attachment points will reconnect your new unit.
   
• If you are replacing a thermostat that contains mercury, be careful not to break the tube containing the mercury. Contact your local waste authorities or the manufacturer of your new thermostat about proper mercury disposal.

Properly set and use your thermostat:

Use the guidelines recommended by the U.S. Environmental Protection Agency’s ENERGY STAR^® program to maximize your programmable thermostat’s energy-saving potential:

Rules of Thumb for Proper Use¹:

1. Keep the temperature set at its energy savings set-points for long periods of time (at least eight hours), for example, during the day, when no one is at home, and through the night, after bedtime.
    
2. All thermostats let you temporarily make an area warmer or cooler, without erasing the pre-set programming. This override is cancelled automatically at the next program period. You use more energy (and end up paying more on energy bills) if you consistently “hold” or over-ride the pre-programmed settings.
    
3. Units typically have 2 types of hold features: (a) hold/permanent/vacation; (b) temporary. Avoid using the hold/permanent/vacation feature to manage day to day temperature settings. “Hold” or “vacation” features are best when you're planning to be away for an extended period. Set this feature at a constant, efficient temperature (i.e. several degrees warmer temperature in summer, several degrees cooler during winter), when going away for the weekend or on vacation. You'll waste energy and money if you leave the “hold” feature at the comfort setting while you're away.
    
4. Cranking your unit up to 90 degrees or down to 40 degrees, for example, will not heat or cool your house any faster. Most thermostats, including ENERGY STAR qualified units, begin to hear or cool at a set time, to reach setpoint temperatures sometime thereafter. Units with adaptive (smart/intelligent) recovery features are an exception to this rule — Adaptive recovery units are constantly calculating the amount of time required to heat or cool the house, so that it reaches that temperature when the homeowner programmed it. By “examining” the performance of the past few days the thermostat can keep track of the seasons. In this way, your house is always at the comfort levels when occupied, but saving the most energy when unoccupied.
    
5. Many homes use just one thermostat to control the whole house. If your home has multiple heating or cooling zones, you'll need a programmed setback thermostat for each zone to maximize comfort, convenience and energy savings throughout the house.
    
6. If your programmable thermostat runs on batteries, don't forget to change the batteries each year. Some units will indicate when batteries must be changed.