Programmable thermostats, which now make up about half the U.S. sales of all thermostats, could be more trouble for some than they're worth.

A study led by Alan Meier, a senior scientist at Lawrence Berkeley National Laboratory, concluded that in many cases, these Energy Star-labeled thermostats are making it hard to save energy. The reason is many people don't know how to use them.

Programmable thermostats allow users to automatically set them at lower temperatures when they're asleep or not at home. A typical setting could have the thermostat switch 10 to 15 degrees lower at night or during the workday but stay at normal levels when people are at home and awake. Programmable thermostats are supposed to make this process simple for users while reducing their energy consumption by 10 to 15 percent.

But many people aren't taking the extra step required to make the energy savings possible, according to the study.

"Many people think that simply installing these would save energy," Meier said. "A programmable thermostat requires installation and then correct settings, then periodically you need to reset it."

A big part of the equation is the difficulty of proper use. Many people don't understand how the thermostats are used, Meier said, although they might be using them in a way they think they understand without realizing they're not saving energy.

Meier and his researchers found that roughly half of the people they surveyed had their thermostats set on hold, mistakenly thinking they were working properly. Leaving a thermostat on hold essentially cancels any preprogrammed settings.

Twenty percent of respondents had the wrong time set by over an hour on their thermostats. This also keeps them from working properly.

Experts find them easy to use, but not others

Meier and his team gathered the research through a series of small studies. First, they collected data from 20 low-income homes in Minnesota that were being "weatherized," or upgraded by public assistance with energy efficient items. Meier asked the crews working on these homes to photograph the thermostats.

Then the researchers used the online public marketplace Amazon Mechanical Turk to offer $1 to those willing to submit photos of their thermostats and fill out a questionnaire about how they use them. They gleaned about 100 responses within two days.

They next brought in 32 people to their lab to watch them physically work with five different thermostats. The researchers asked the people to perform the "tasks they need to do to make the thermostats work," Meier said.

Some brands of thermostats were easier for people to work with than others, although Meier said he wouldn't "name any names." But all of them ranked as easy to use in respected consumer reports, Meier said. To him, that's not surprising.

"These are experts testing these in a well-lit room with a table," he said. "Most of the time thermostats are in cramped areas with dim lighting."

Meier said his approach to measure usability could catch on and be used for many other products. One he mentioned is controls for lights, especially in commercial buildings.

"We're used to this idea of idea of a light switch, but in fact, it's becoming much more complicated than that," he said.

He plans to delve into light controls soon, but first he's going to do more work with thermostats, he said.

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500