Suggested date of release:
After November 21, 1999
Claudia Chandler (916) 654-4989
Media and Public Communications Office
(Eighth in a series of 10 feature articles for 1999)
Get Comfortable with your Setback Thermostat
Here's an intriguing question to consider as you heat your house this winter. Which uses less energy?
- Leaving your thermostat at the same comfortable level, all day long, or
- Turning the temperature down when you leave the house and raising it back to a more comfortable level when you return home?
Did you correctly guess #2?
It's a common misconception that leaving your heating system on all day is more economical than setting your thermostat back. In truth, leaving the temperature inside your home constant will most likely cost you money. On the down side however, adjusting the temperature of your house over and over can be a real pain. Who could possibly remember to efficiently turn the heat up and down and up again at the proper times?
But here's the good news - if your home has a setback thermostat, you've already got a simple way to do just that. Used properly, the little box hanging on your wall will save you energy - and energy dollars.
New houses with a central heating and cooling system must come with an automatic setback thermostat. If you have an older home that doesn't have one, you can usually replace your existing wall thermostat with a setback model very easily.
For those of us who still have trouble programming our VCRs, however, the sight of a setback thermostat can be daunting. The small device may have buttons for setting the time, the temperature, for separate days of the week, and to change from heating and cooling. But while the automatic thermostat may seem complicated at first, remember that you can significantly reduce your energy bills by investing a little extra effort to learn and master its features.
Your savings can be impressive. Recent studies show that properly using your automatic thermostat should cut your heating costs from 20 to 75 percent. In summer, such devices may shave your cooling costs by 15 to 25 percent. (Your actual savings will depend on such factors as the climate in which you live, the amount of insulation in your house, what temperature you set the thermostat, and the rate structure of your utility company.)
How they work
All setback thermostats will automatically start and stop your heating or cooling system at least twice over a 24-hour period.
Here's the typical way to operate your automatic thermostat properly in the winter:
- Program it to lower the temperature at night after you've gone to bed.
- Have it start the heating system again in the morning, raising the temperature just before you get up.
- Let it shut off the system again during the day if no one is home.
- Set it to start up just before you return home in the evening. You'll use less energy than if you run your system all day long.
For winter operation, consider setting the thermostat to 55 degrees at night when you sleep and at 68 degrees when you're home. (In colder parts of California, it's not recommended to set the temperature below 50 degrees, because indoor water pipes may freeze.)
For summer operation, set the temperature to 78 degrees when you're home and at 85 degrees or higher when the house is unoccupied. In the summer season, you might need to program your thermostat to cool only for one period of the day, such as the late afternoon and evening hours when the family returns home.
What to look for
Automatic setback thermostats come in many varieties, with many models within each variety. But they all regulate your heating and cooling system to provide comfort when you decide you need it.
Most programmable thermostats allow you to enter at least one "at home and away from home" schedule for the weekdays and a different one for the weekend. Other models may feature full seven-day programming, enabling you to customize the operation of your heating and cooling system for any day of the week.
Some brands will start your furnace or air conditioner at the time you specify, while others reach the temperature you want at the time you want, meaning that heating or cooling will begin sooner than the time you programmed into the unit.
Setback thermostats may also come with a variety of helpful "extras" such as:
- A light to remind you when to change the furnace filter.
- A keypad lock to prevent small children from accidently (or mischievously) changing the thermostat programming.
- Automatic changeovers with the season, eliminating the need for you to flick a switch when your comfort needs change from the heating to the cooling.
- Lighted displays that glow at night, a convenience in dark hallways.
- "Armchair" programming that allows you to detach the thermostat from its base and enter your schedules from the comfort of a chair, instead of requiring you to stand in the hall, at the unit.
- A low battery warning indicator. (Batteries keep the internal clock ticking and preserve the programmed schedules during a power outage.)
Many thermostats have daily schedules already built in, requiring you to change only those days that don't reflect your personal lifestyle. In addition, most models allow you to override the programming when your schedule changes. To save additional energy, you may want to manually turn the thermostat off when you are on vacation.
If programming the setback thermostat you have in your home is confusing to you, look for simplified instructions, often found inside the thermostat cover. Many manufacturers also offer toll-free customer assistance.
A special note for heat pump owners
If your house is equipped with a heat pump system, look at the manufacturer's specifications before considering a programmable thermostat. Most makers of heat pumps offer setback thermostats specifically designed for their units. An improperly used or mismatched setback device can actually increase the cost of operating your heat pump!
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This article is based on the California Energy Commission's Home Energy Guide, to be published early in 2000.
You can find additional information about energy in California on the Energy Commission's Web Site at www.energy.ca.gov.
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