The National Green Building Standard (NGBS), a green building certification program used by many builders and developers, is undergoing a transition from the 2012 to the 2015 version.
For all states that have adopted the 2012 or later IECC energy code, any project that registers before June 30, 2018 and completes construction by December 31, 2021, may certify under the 2012 version. Projects that do not meet both deadlines must use the 2015 version.
Projects in states that are under the 2009 IECC may continue to certify buildings under the 2012 version until the state adopts a more stringent code.
Projects may register for either version at any time at no cost to the builder or developer. Certification fees are due at the time of rough inspections. NGBS 2015 is more stringent than 2012 in several areas, benefiting projects that can register and complete construction within the time frame that the earlier version applies.
NGBS 2015 has several new requirements, primarily in the energy efficiency section:
- To meet Bronze level certification, all new buildings must meet the 2015 IECC energy code requirements for the building envelope through ResCheck, or ComCheck, or for the entire building through a whole building energy model or HERS ratings.
- Building envelope leakage (blower door) testing is now required for all buildings 3 stories or less. For multifamily buildings, this testing can be a sample of 1 in 7 units. For buildings that test tighter than 5 ACH50, ventilation systems are required to be installed, complying with the building code. Multifamily buildings four stories or more can substitute visual inspections for the envelope leakage test.
- Insulation must be installed to Grade 1 quality. While this requirement can be met with some effort using batt insulation in walls, it is practically impossible to achieve this grade in floors and other complex areas with batts. If continuous exterior insulation is installed, insulation may default to Grade 2. Unless exterior insulation is installed, we recommend using blown or sprayed insulation in all exterior walls, floors and ceilings.
- Duct leakage testing is required for all ducts located outside of conditioned space.
The remaining categories do not require significantly more effort that the 2012 version, but we recommend reviewing any projects that must certify under the 2015 version to confirm that the design will meet program requirements.