WASHINGTON - Homes built to voluntary Energy Star specifications made up about 26 percent of all new homes constructed in the U.S. in 2011. Under the latest update of the specifications that went into effect earlier this year, Energy Star homes consume at least 15 percent less energy than those built to the 2009 International Energy Conservation Code (IECC).
There is currently no national building-energy code. States
have adopted a variety of codes with different levels of stringency, mostly
based on the IECC, a building-energy code created by the International Code
Council. Often the stringency of these state-building codes and Energy Star
participation is correlated: all but one of the eight states lacking a
statewide energy code have low Energy Star participation, while Arizona's
strong utility support for energy-efficient construction has fostered a high
penetration of Energy Star-qualified homes, even though there is no statewide
The U.S. Environmental Protection Agency (EPA) initiated the
Energy Star specification for residential construction in 1995, creating homes
that were 30 percent more efficient than the 1992 Model Energy Code (MEC). The
specifications were revised to create Version 2 in 2006, and Version 3, which
was released in 2012.
A home can receive Energy Star certification in one of two
ways: the prescriptive path or performance path. Both paths have program
requirements common to all qualifying homes across the nation. The prescriptive
path incorporates predefined improvements based on a home's IECC climate zone,
while the performance path uses home energy modeling to account for savings
based on a more flexible use of energy savings measures. A certified
Residential Energy Services Network (RESNET) home energy rater verifies that
specific requirements of the guidelines are met.