The U.S. Department of Energy says ASHRAE’s 2010 building efficiency standard is now the one state codes should follow.

The announcement was made in the Oct. 19 Federal Register, the daily publication that announces government rules. The Energy Department said the American Society of Heating, Refrigeration and Air-Conditioning Engineers’ updated standard 90.1, which covers energy efficiency for most structures, offers an 18 percent efficiency improvement over earlier guidelines.

Under the federal Energy Conservation and Production Act, states are required to update commercial building codes by October 2013.

“The foundation of energy efficient buildings continues to grow stronger with the news that DOE is now referencing the 2010 standard,” said ASHRAE President Ron Jarnagin. “ASHRAE hopes to make that foundation even stronger through our current work with IES (Illuminating Engineering Society) developing the 2013 standard.”