MCLEAN, Va., Jan. 21 (UPI) -- A U.S. company says it has developed a power cord that identifies "vampire electronics" gobbling up electricity in most U.S. homes.

Vampire electronics is a term for common household electrical appliances such as microwave ovens, coffeemakers and toasters that continue to consume small amounts of electricity even when they're not "on."

The Lawrence Berkeley National Laboratory estimates these electronic devices consume 5 percent to 10 percent of all electricity used in U.S. households, CNN reported Friday.

U.S. company Dexim says its cellphone charger will come with a power cord that makes this electrical consumption visible.

When electricity is flowing through the charger's cord, blue lights travel down the cord, too, letting users see the energy that's being used to charge their smartphones.

The lights will move down the cord more quickly when the phone battery is lowest, since more electricity is needed to charge it.

Researchers have been examining the idea of "visualizing" power and cutting down "vampire" electricity usage.

Dexim spokesman Patrick Tarpey says the charger isn't intended to guilt consumers into using less energy, it's just meant as a neat visual indicator of power use.

It could have that guilt effect, however, some experts say.

The charger "will influence some people (not all people) to recharge their phones differently," B.J. Fogg, director of the Persuasive Tech Lab at Stanford University, told CNN.

"It's a cool idea," he said.