In a continuing effort to advance the use of environmentally responsible technologies in residential construction, the National Association of Home Builders (NAHB), the International Code Council (ICC) and the NAHB Research Center are nearing the end of a process that will result in an ANSI standard for green dwelling design and construction practices. The entire process, from the formation of a consensus committee to public review and final ANSI approval, is expected to be completed in early 2008. The result will be a voluntary green building standard that can be adopted by local green home building programs or local building departments as a conformance guide. After completion of the ANSI process, the standard will be promulgated as a joint publication between NAHB and the International Code Council (ICC).
The Consensus Committee developing the new standard started with the NAHB Model Green Home Building Guidelines developed by the NAHB Research Center in 2004 with participation from a Stakeholder Group of over 64 organizations representing various vested interests in residential construction in the United States. (Described below)
As of early November, the Committee was immersed in the process of addressing nearly 1,000 public comments submitted by a broad group of interested parties on the first draft. The revised draft is expected to be posted for a new public comment period on December 21, 2007. An opportunity to submit further public comments will begin at that time. In accordance with ANSI procedures, the public comment period will continue for 45 days. The resulting ANSI-approved standard will provide a common benchmark for recognizing and rewarding green residential design, development, and construction practices in a manner that is transparent, verifiable, and meaningful to builders, product manufacturers, and consumers.
Based on the wide acceptance of the predecessor guidelines, it is expected that the new standard will become the preferred one for adoptions by organizations and jurisdictions desiring to maximize the transformation of their housing stock into a sustainable and environmentally sensitive asset.
All information dedicated to the standard development process is posted to an NAHB Research Center website at www.nahbrc.org/GBStandard. All questions related to the standard development process should be forwarded to firstname.lastname@example.org.
The Model Green Home Building
The NAHB Model Green Building Guideline has 7 sections.
- Lot Design, preparation, and Development
- Resource Efficiency
2.2.12A Flashing Details
2.4.1 Recycled Material
2.6.1 Renewable /ag byproducts
2.6.2 Certified Wood
2.7.0 Fewer resources
- Energy Efficiency
- Water Efficiency
- Indoor Environmental Quality
5.1.5 low formaldehyde emissions
- Operation, Maintenance, and Homeowner Education
- Global Impact
7.1.1 ISO 14001 certification
7.1.2 no/low VOC paints
Part One - The Checklist
Part One of these guidelines contains the checklist of line items. Each entry includes the line item title, the point value, and the items that should be provided by the builder to verify that the line item was implemented. The verification column assumes there is a green building program coordinator or other third-party. However, the guidelines and point system can be used independently even if a formal green building program does not exist in a particular region.
It is again recommended that a builder first become familiar with the line items prior to designing a home to help introduce concepts that a builder can incorporate into the home's design, construction, and operation.
To help a builder holistically incorporate green building into homes, the NAHB Research Center team established different point levels to achieve for each guiding principle for each level of green building. The point system is described below.
There are three different levels of green building available to builders wishing to use these guidelines to rate their projects - Bronze, Silver, and Gold. At all levels, there are a minimum number of points required for each of the seven guiding principles in order to assure that all aspects of green building are addressed and that there is a balanced, whole-systems approach. After reaching the thresholds, an additional 100 points must be achieved by implementing any of the remaining line items. The table below outlines the various green building level thresholds.
Points Required for the Three Different Levels of Green Building
Lot Design, Preparation, and Development
Indoor Environmental Quality
Operation, Maintenance, and Homeowner Education
Obtain additional points from sections of your choice
*If the home does not have a ducted distribution system for space heating and cooling, deduct 15 points from the number of points required in the Energy Efficiency section.
A reduction in the required points for a home without ductwork for the space heating and cooling systems reflects the fact that there are more points available for homes that do have ductwork. It is not intended as an indication of preference for one type of system over another.
To determine point values for each guiding principle, a builder simply adds the points for each line item applied to the home for each guiding principle. Comparing the project's points for the individual guiding principles to the chart above will determine whether the project is deemed a Bronze, Silver, or Gold level green home.
Part Two - The User Guide
Recognizing that some of the line items needed more than a one- or two-sentence explanation, the User Guide further explains each concept. For each line item, the User Guide contains an entry with the following subheadings:
- Intent - Explains the general reasons for including each line item in the guidelines and the impact that implementing the line item will have on the environment.
- Additional Information / How to Implement - Contains text, pictures, and formulas to help facilitate the line item's implementation.
- Resources - References to books, websites, articles, and technical guides for further in-depth information related to the line item. Please note that the URLs were active and current at the time this document was created. With the significant changes occurring on the Internet and in the home building industry products and services markets, location and availability of resources will most likely change over time.
Appendix A provides additional ideas to consider for builders and developers who can affect change at the subdivision level, i.e., multiple home levels.
If a local green home building program does not exist, a builder can use the checklist and User Guide herein and self-certify a home. However, if a local association has used this document to create a local green building program, the builder can use the checklist and system from that program to show a home's relative green value.