October 2007
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Thermostats
Some make saving easier

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Better Thermostats
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Programmable thermostats can help save energy by automatically raising or lowering temperatures at night and when you're away. But confusing controls on some can make it easy to burn more energy than you bargained for.

The fact that some top thermostats can be hard to use is a primary reason the U. S. Environmental Protection Agency is reconsidering its Energy Star certification. "Programmable thermostats can save significant energy, but only when programmed correctly," says Maria Vargas, an EPA spokeswoman. "We've found there's a margin for error that leads to energy waste." Indeed, many people assume that no programming is needed for these products, Vargas adds. The agency is proposing an educational program, and will work with the industry to make thermostats friendlier.

Manufacturers have taken some steps to make programmable thermostats less daunting. Today's top thermostats have built-in energy-saving programs that are designed to cut heating and cooling costs by up to 20 percent, eliminating the need to create programs from scratch. But you'll still have to set the time, date, and the system they'll control. Odds are you'll also want to tailor those programs to your schedule.

Our Ratings (available to subscribers) include 25 models, with CR Best Buys that cost as little as $35. But months of testing confirmed that even some top thermostats make programming far more onerous than others, regardless of price. And while most are good at showing and maintaining the temperature you set, we found several exceptions. Here are the details:

Two are tough to program. Clear onscreen prompts and intuitive controls help make saving energy easier. But simply setting the time on one unit involves a long list of steps that could encourage mistakes. (The model is being discontinued.) A screen that shows numbers instead of days also helped to make programming dates on another unit seem like rocket science.

Two are hard to see. A top thermostat's display should be easy to read at arm's length. Glare and tiny letters made reading two of the two models we tested a challenge. All programmable thermostats let you override their energy-saving modes. Some use bold letters or lights to tell you the override is on. Others are among those with override prompts that are relatively easy to miss.

Some top thermostats blow hot and cold. Most models kept temperatures steady by quickly activating the heating or cooling system. Models judged less than very good let temperatures rise and fall several degrees more than others, which could prompt you to override the program.

One was less accurate. Displayed temperatures for most top thermostats were accurate to within one or two degrees. All three samples of one model read up to four degrees too high, which could make you uncomfortable enough to raise or lower temperatures.

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Lux Smart Temp Touch Screen TX9000TS thermostat
CLEAR CONTROL  A top-scoring Lux model was among the easiest to program
in our tests.