Green building guidelines and rating systems usually offer a general education on green building, its value, and the goals and measures used to design and build a green home. Benefits to the builder, homeowner, and community of green building are often listed, both environmental and economic.
A rating system synthesizes the complexity of the green building guidelines into an easy to understand measuring system. Typically, rating systems organize green building measures into sections (site, foundation, framing, electrical, plumbing, interior finishes, exterior finishes, roofing, etc.) containing options from methods suggested in the guidelines. These sections provide a menu or spreadsheet of measures that need to be installed or implemented in order to earn points toward a particular rating.
The building measures all have a point value and are assigned to the various point rating levels based on their impact, costs, availability, and other relevant concerns. For example, a one-point value measure is typically basic, inexpensive, requires little engineering, is easily available, and has a lower environmental impact. As the point values increase on a certain measure, the degree of cost and implementation difficulty of the measure increases along with the environmental, economic, and health benefits.