Building green means incorporating environmental considerations and resource efficiency into every step of the home building and land development process to minimize environmental impact. That means that during the design, construction, and operation of a home, the home's overall impact on the environment is taken into account.
Most builders are using green building practices in their homes as part of their current standard practices; ENERGY STAR® windows and appliances, recycled content materials, and water-conserving fixtures are all important parts of a green built home. To move to the next step of sustainable building, the builder should consider a whole-house systems approach. The home is composed of several independent components which, when planned and fully considered, can work together to increase performance and efficiency. For example, making a home's building envelope tighter through air sealing and quality building techniques can affect the way the builder designs the home's ventilation system. It is through such a forward-thinking process that builders can gain cost efficiencies.
How do I get started?
The NAHB Model Green Home Building Guidelines or the ANSI approved ICC 700-2008 National Green Building Standard are ideal places to start. Each consist of a variety of line items that a builder can choose from in creating a green home, organized into seven overarching sections, or guiding principles. The Guidelines reference Lot Design, Resource Efficiency, Energy Efficiency, Indoor Environmental Quality, Homeowner Education, and Global Impact. The Standard addresses these same areas, but also provides guidance for multifamily construction, remodeling and renovation projects and site development for the creation of green subdivisions. Each line item is either described as mandatory or has a point value attributed to it. Point values were determined by taking three different concepts into consideration:
- Environmental Impact – Both the Standard and the Guidelines provide a framework for builders to reduce a home's environmental impact, taking into account all available data. Using qualitative and quantitative information, the consensus committees who formed the documents assigned value to each line item based on the positive impact to the environment.
- Building Science and Best Building Practices – Certain practices dramatically affect a home's operation. For example, the sealing of a home's building envelope has an impact on the home's HVAC system. In addition, proper flashing details and installation of weather barriers enhance durability and minimize the possibility of indoor environmental problems. Line items that help a home perform effectively as a system for the long term were assigned a higher point value.
- Ease of Implementation – The Consensus Committees compared each line item to current practices and estimated how difficult it would be for a builder to implement the line item. For instance, would it take longer to install a new technology? Would subcontractors need to be educated on the use of a new product? Would a new technology cost more to buy? Line items that were relatively easy to implement (and therefore more likely to be implemented) were assigned a greater point value than the items that are more difficult to implement.
Knowing the background that went into determining the line items and their relative value, the builder can review the criteria in each of the areas to determine which practices they could integrate into their home building processes. Additionally, because home builders differ in their relative knowledge and comfort level with green building concepts, both the Standard and the Guidelines offer thresholds to delineate different levels of effort. The first level of green building, Bronze, features items that demonstrate the builder paid special attention to a project's environmental impact. The next two levels of green home building, Silver and Gold, include additional line items that place increasingly greater emphasis on green practices. The Standard also introduced a new level, Emerald, to denote the pinnacle of achievement in residential green construction. Learn about the points needed to reach each level of green building according to the Standard and the Guidelines.
In addition to the NAHB National Green Building Program, there are many green home building programs in operation throughout the United States, which may offer climate-specific guidelines and resources and provide a network of local industry professionals also working to improving housing stock with green practices. See the local program listings for links and more information on local offerings.