In the past, I have been critical of the NAHB’sNational Green Building Standard (NGBS), just as I have been of most other green building programs. While I don’t expect to lose my critical eye, I do believe I have mellowed a bit and developed new opinions about the certification process and each program’s role in the industry.
I recently obtained a copy of the new 2012 NGBS and have reviewed it fairly thoroughly. My clarifying questions were answered very promptly by the nice folks at Home Innovation Research Labs (formerly known as the NAHB Research Center). Now I don’t know about their new acronym (HIRL?), but they were goodnatured when I commented about it on Twitter recently.
What’s new and different?
There has been a noticeable leap in energy efficiency from the 2008 version, based on the fact that the standard now requires a home be at least 15% more efficient than the 2009IECC. Certification now requires a Manual D duct design for forced-air HVAC systems. It’s also necessary to follow a list of required air-sealing measures that appear to be lifted directly from the IECC, and to install insulation at Grade 2 or better installation quality.
Read the complete article here.