WASHINGTON  The Energy Department has concluded in an internal audit that it does not properly track whether manufacturers that give their appliances an Energy Star label have met the required specifications for energy efficiency.

Some manufacturers could therefore be putting the stickers on unqualified products, according to the audit, by the Energy Department’s inspector general, Gregory H. Friedman.

The Energy Star program, jointly managed by the Energy Department and the Environmental Protection Agency, has benefited from a renewed emphasis by the Obama administration, as a mechanism for reducing the waste of energy and curbing resulting greenhouse gas emissions. Under the federal stimulus bill, $300 million will go to rebates for consumers who buy Energy Star products.

Some consumers choose energy-efficient appliances for the same reason they might choose a car with good fuel economy: to save money or reduce the environmental impact.