*The following piece is combination of comments from MEEA staff and direct DOE findings. A link to the full findings is at the bottom of the piece.
The US Department of Energy (DOE) released their discussion of changes in the 2012 IECC when compared with the 2009 IECC as the changes related to energy efficiency in the Federal Register on October 19, 2011. The purpose of the discussion was to determine if the 2012 IECC saved more energy than the 2009 IECC. The discussion covered changes that increased energy efficiency, decreased energy efficiency, or those that had no significant impact on energy efficiency.
According to the discussion, the 2012 appears to improve residential energy efficiency when compared with its predecessor. While DOE acknowledges that there are a small number of changes that have potential negative impacts, or no impact at all, based on their preliminary analysis, there are several major changes that correct any negative impacts to energy efficiency.
According to DOE, there are several major changes that are estimated to increase energy efficiency. These changes are: building thermal envelope, infiltration control, wall insulation with structural sheathing, ventilation fan efficiency, lighting, air distribution systems, and hot water pipe insulation and length. Other aspects of the code may also help increase energy efficiency, however; only those that made the largest impact were specified.
Changes made to the energy code that could have a negative impact on energy efficiency are: steel-framed wall insulation, location of the air barrier. Fenestration SHGC in climate zone 4 is the only change listed that has an unclear impact on energy efficiency. The energy loss of those changes that had a negative or unclear impact is made up and surpassed by the changes that had a positive impact on energy efficiency and an overall increase should be observed.
The information presented in the discussion is helpful in that it pinpoints the major points of the change to the energy code and gives information that could be used to help implement energy codes and educate those who are new to the code. Perhaps a next step in the process would be to determine how much more energy efficient the 2012 IECC Commercial code is compared to the 2009 IECC Commercial Code. If you would like more information or would like view the entire document, please use the link below.