Energy Star standards, which rate the energy efficiency of buildings and products, need an update, according to Consumer Reports.



On the heels of criticism of Energy Star last week from a New York congresswoman, the magazine said the ratings program needed to raise the bar on qualifying products and develop better testing standards.



More than 35% of all products sold in certain categories get the Energy Star rating, according to Consumer Reports. Having a glut of qualifying items results in consumers having a harder time choosing truly eco-friendly goods, the magazine said.



The Energy Star system is run by the Environmental Protection Agency and the Department of Energy. Consumer Reports also found that some appliances tested under Department of Energy standards ended up performing differently in home situations.



More than 40% of Americans have purchased an Energy Star product, Consumer Reports said, and 23% have upgraded to a more energy-efficient heating or cooling system. The vast majority -- 77% -- made the switch to cut down on their energy costs.



Potential cost savings abound, Consumer Reports found: $200 a year just by programming the thermostat, $400 by fixing leaky ducts, $75 by avoiding pre-rinsing dishes before they go in the washer.



But conserving energy and using it wisely, even without Energy Star, can be complicated. In the last 12 months, 91% of all homeowners made an energy purchase or improvement that qualified for a government rebate or tax credit. But just a quarter of those said they took advantage of an incentive program, Consumer Reports said.



Most were confused by the tangle of rules behind many programs, and others thought the incentives were too small to justify the hassle. Consumer Reports surveyed more than 1,500 homeowners on the subject in June.

-- Tiffany Hsu