Rachel Swan is one of them. Through a program called GLEE—Girls Learning Environment and Energy—the San Mateo, Calif., 12-year-old and her troop learned how to use less energy through five hourlong sessions. They learned to turn off the lights when they left the room. They learned to hang dry their clothes. They learned to adjust the temperature in the refrigerator. And they learned how to persuade their families to save energy, too.

“I know all of my other friends who were in GLEE with me always went home and talked to their parents. They talked with their siblings, too,” Swan said in a phone interview. “We all had a lot of fun with it because it felt nice being the one to teach your parents things because they always teach you things. You know, return the favor.”

Her mom chuckled at this but agreed.

“It’s kind of fun to learn some things from your kids, to get them to try and convince you that this is the way we should do this,” said Clare Swan, who helped coordinate the GLEE program for Rachel’s troop.

The report, published in the journal Nature Energy, revealed that under a well-designed program, Girl Scouts are very good at learning to save energy. The study also found Girl Scouts are good at teaching their parents to save energy, too.

In the end, the researchers found the Girl Scouts increased their energy-saving behaviors by 49 percent after participating in the program. Parents of Scouts in this group also increased their energy-saving behaviors by 12 percent.

The study’s authors are excited about the potential impact of getting more Girl Scout troops and other children’s organizations to participate in the GLEE program. U.S. households are big energy consumers, and the Girl Scouts report that 1 in 2 U.S. women has been a Scout for an average of four years.

“I think one of the main things that we can take away from this is children are a really critical audience for environmental programs,” said lead author Hilary Boudet of Oregon State University’s School of Public Policy. “Children can play a really important role in bringing about a more sustainable future.”

FROM POMPOMS TO LONG-TERM ENERGY SAVINGS

Boudet, who was herself a Girl Scout as a child, explained the GLEE program uses principles of social cognitive theory to teach energy-saving behavior. The principles include practicing positive behaviors, modeling those behaviors to others, and setting and committing to goals.

For example, every meeting started with an activity called an “action jar.” The jar was filled with a colorful pompoms, and each week, an adult would list a series of changes the girls may have made in their everyday lives.

“So did you adjust the temperature of your refrigerator? Did you install a compact fluorescent light bulb? And then the girls, if they had done that, they could take a pompom and put it in their individual cup,” Boudet explained. “Not only were they tracking their own progress, but then we would have them all dump pompoms into the big jar, and they could see their troop progress, as well.”

The program’s effects were surprisingly long-lasting, the researchers found. When they checked in with the Scouts seven months later, they found the Scouts still showed a 27 percent increase in energy-saving behavior compared with before the program started.

Changes varied from parent to child. For the Scouts, some of the biggest changes involved turning off power strips at night, adjusting refrigerator temperatures and washing clothes in cold water, according to Boudet. Parents reported the largest changes in adjusting refrigerator temperatures.

There is no guarantee that the new behaviors will be permanent, but it is unusual that they remained so many months after an intervention, Boudet said.

“It’s also worth noting that, particularly the program geared toward promoting energy-saving behaviors at home, was quite efficient. Our results indicate that if only two Girl Scouts are exposed to the program, one will change her behavior,” she said.

LIGHTS OFF, COLD-WATER CLOTHES WASHING AND (MAYBE) SHORTER SHOWERS

In an accompanying article published in Nature Energy, Alice Grønhøj, who researches consumption and the environment at Aarhus University in Denmark, praised the study for its “methodologically robust design” that “attests to the credibility of the central findings.”

Grønhøj said the study does leave some questions open. “It is convincingly documented that the interventions resulted in energy-saving behaviors in households but it is less clear how these changes come about,” she wrote.

But Grønhøj concluded the study “provides valuable suggestions for how children may be taught to engage in energy conservation … as well as helping them to prepare for an adult life with increasing pressure on resources.”

Rachel and her mom said they’re still practicing the energy-saving habits she learned in Girl Scouts.

“I always like to talk to my family about washing the clothes with cold water instead of warm water,” Rachel said.

“I think the things that help me the most are the stickers by the light switches because I used to leave the lights on and it helped me a lot,” she added.

But there’s always room for improvement.

“Taking a shorter shower—that one didn’t happen,” Swan said, laughing. “We’re working on that.”