he green building movement has generated quite a following in the last 5 or 10 years, and what used to be a somewhat fringe idea is now becoming part of mainstream culture. Advertisements for products and services across the spectrum are full of sometimes dubious claims of how environmentally friendly they are, and efforts are being made in many industries to create a metric to quantify how “green” something really is.
The building industry has been a leading force in the establishment of meaningful rating systems for measuring the environmental impact of common materials, methods, and design practices used to create modern buildings. The LEED rating system was developed in 2000 by the U.S. Green Building Council, and soon became the industry standard, perhaps because it was the only standard. It has evolved from a broad scope that attempted to encompass all aspects of building construction into a suite of specific rating systems that target specific project types.
In 2007, the International Code Council (ICC) and the National Association of Home Builders (NAHB) partnered to create a nationally recognizable standard for measuring sustainable building practices called The National Green Building Standard. It provided a much needed tool for comparing the relative merits of single and multi-family homes built using established or innovative products and practices. Since it is specific to the residential sector of the construction industry and a companion document to the ICC suite of model building codes, many builders and homeowners are choosing to pursue certification under the National Green Building Standard.
The Green Building Standard is similar to LEED in many ways. Both utilize a point system that is used to achieve one of four different levels of certification. In the National Green Building Standard, the levels are Bronze, Silver, Gold, and Emerald. Points are earned for employing green building practices that fall into categories covering the basic tenets of sustainable design and construction:
1) Site selection, design, & development
2) Resource Efficiency
3) Energy Efficiency
4) Water Efficiency
5) Indoor Air Quality
6) Owner education on systems operation and maintenance
7) Innovative practices
In both the LEED and NAHB rating systems, an independent verifier is used to determine a project’s level of achievement.
In general, the NAHB Green Building Standard provides rewards for practices that exceed the basic requirements of building codes, especially as they relate to minimum insulation levels, plumbing fixture flow rates, and ventilation requirements. Emphasis is placed on high efficiency heating / cooling, minimizing generated waste, using durable, renewable, salvaged or recycled materials, and avoiding products that contribute to poor indoor air quality or have adverse environmental impacts.
At Hendricks Architecture, we have designed a couple homes recently that will be seeking certification under The National Green Building Standard. Scott Schriber of Selle Valley Construction will be building both of them, and he has constructed several NAHB certified green homes in the last few years. He estimates that it costs an additional 3%-5% upfront to build a home that achieves Green Standard certification.
Our experience has been that when clients are considering if they should build a high performance/ low impact home, upfront cost is almost always a factor. When trying to decide if “going green” makes financial sense, it is important to remember that a home built to The National Green Building Standard (or other rating systems) will benefit from substantial long term energy and maintainace cost savings, improved indoor air quality, and enhanced resale value. Financial considerations aside, many homeowners are opting to build high performance green homes simply because they value the peace of mind that comes with creating a healthy, durable place for their families to live.
Tom Russell, Project Architect, LEED AP
Hendricks Architecture, mountain architects in Sandpoint, Idaho.
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