From dishwashers and washing machines, to computers and televisions, more than 50 different types of products are covered under the Energy Star program.
But Consumer Reports' tests show the Energy Star doesn't always signal the biggest energy or money savings.
"We found problems with the Energy Star program and its test protocol that can result in manufacturers labeling their products more energy-efficient than they are when you really use them," said Kim Kleman, Consumer Reports.
Consumer Reports' tests found big discrepancies with two newer French-door refrigerators. Samsung says their refrigerator, which qualifies for an Energy Star, consumes an estimated 540 kilowatt-hours per year. But Consumer Reports' tests, which are more demanding than Energy Star to better reflect real-life use, show this refrigerator uses 890 kilowatt-hours per year.
LG says their refrigerator, which also has an Energy Star, uses an estimated 547 kilowatt-hours per year. But Consumer Reports' tougher tests show energy use could be more than double that.
But not all Energy Star information was off the mark.
Maytag says one newer French-door refrigerator uses an estimated 547 kilowatt- hours per year. Consumer Reports' tests shows 565 kilowatt-hours per year.
"Federal officials have acknowledged to us that test procedures have not kept pace with technology. We think that needs to change," Kleman said.
But despite the problems, Consumer Reports says the Energy Star can still be a useful first check.
"And if the product you want has an energy guide, compare the money savings on that label, too," Kleman said.
Consumer Reports also recommends that the government implement independent verification of Energy Star test results.