The U.S. Department of Energy announced Nov. 19 it would raise the minimum energy-efficiency standards for residential furnaces and boilers beginning in 2015.

Gas furnaces will see their annual fuel-utilization efficiency ratings go from 78 percent to 80 percent and oil furnaces’ efficiency will go from 78 percent to 82 percent. Other products affected include furnaces used in mobile homes and oil- and gas-consuming boilers, whose efficiency levels will rise an average of 5 percent.

“As a nation, we must find better and more ways to both conserve energy and use it more efficiently and productively,” said Andy Karsner, the Energy Department’s assistant secretary for energy efficiency and renewable energy. “These amended standards will not only cut down on greenhouse gas emissions, but they also allow consumers to make smarter energy choices that will save energy and money.”

The department estimates that the changes will mean 7.8 million less tons of carbon dioxide will be released into the atmosphere.

But many environmental groups expressed disappointment with the new rules, noting that a lot of furnaces currently on the market already meet the new standards. They suggested higher minimum nationwide standards or the ability for states to set regional guidelines would have had a greater impact.

A bill currently being debated in Congress would allow the practice.

“DOE has delivered a ‘turkey’ of an efficiency rule,” said Andrew deLaski, executive director of the Appliance Standards Awareness Project, an advocacy group.

Kateri Callahan, president of the Alliance to Save Energy, urged the government to take “bold action” to save energy and the environment.

“Our country cannot create a sustainable energy and climate future through incrementalism,” she said.

The groups have suggested a 90 percent efficiency standard - a level already met by a third of all furnaces sold - would save consumers more money and have a greater impact on carbon dioxide emissions.

Efficiency-level ratings refer to how much heat is produced compared with the energy used to produce it. A furnace with a 90 percent AFUE rating wastes only 10 percent of the energy it consumes. Furnaces rated at 80 percent waste twice as much.