About NAECA Guidlines
The U.S. Department of Energy (DOE) regulates minimum energy efficiency requirements for water heaters. The first set of regulations—known as the National Appliance Energy Conservation Act (NAECA)—were created in 1990 and later updated in 2004 to the current standards. A new update to the rules for increasing minimum energy efficiency standards was enacted in 2010 and is in effect as of April 16, 2015.
For more information go here or download the brochure attached.