Resource-efficient site design and development practices help reduce the environmental impacts and improve the energy performance of new housing. For instance, site design principles such as saving trees, constructing onsite storm water retention/infiltration features, and orienting houses to maximize passive solar heating and cooling are basic processes used in the construction of Built Green® Homes.
Successful Built Green Homes® start with the consideration of the environment at the design phase-the time at which material selection occurs. Creating resource efficient designs and using resource efficient materials can maximize function while optimizing the use of natural resources. For instance, engineered-wood products can help optimize resources by using materials in which more than 50 percent of the log is converted into structural lumber rather than conventional dimensional lumber.
Resource efficiency is also about reducing job-site waste. Invariably, there are leftover materials from the construction process. Developing and implementing a construction waste management plan helps to reduce the quantity of landfill material. The average single family home in the United States at 2,320 sq. ft. (NAHB 2003), is estimated to generate between 6,960 and 12,064 lbs. of construction waste. Thus, by creating an effective construction waste management plan and taking advantage of available recycling facilities and markets for recyclable materials construction waste can be reduced by at lease two-thirds, creating potential cost savings for builders and reducing the burden on landfill space.
Lastly, basing the selection of building materials on their environmental impact can be tricky. For instance, a product might be renewable, but on the other hand it takes a relatively large amount of energy to transport the product to a project's job site. One way to compare products is to look at a product's or a home's life-cycle environmental impacts through a process called life-cycle analysis (LCA). An LCA of a building product covers its environmental impacts "cradle to grave" through six basic steps: 1)Raw material acquisition, 2) Product manufacturing process, 3) Home building process, 4)Home maintenance operation, 5) Home demolition, and 6) Product reuse, recycling or disposal.
Energy consumption has far-reaching environmental impacts: from the mining of fossil-fuel energy sources to the environmental emissions from burning non-renewable energy sources. And each home consumes energy year after year, meaning that the environmental impacts associated with that use accrue over time. Therefore, energy efficiency is weighted heavily in Built Green® programs.
Energy consumption occurs not only during the operation of a home but also during the construction of a home and, indirectly, in the production of the materials that go into the home. Also, the energy used to heat and cool a home over its life far outweighs that to manufacture the materials and construct it, the large number of homes built (currently 1.85 million per year) renders the energy used during the construction phase significant.
On average, a home built between 1990 and 2001 consumed about 12,800 kW per year for space and water heating, cooling, lights and appliances. Where natural gas is used, consumption averages 69,000 cubic feet per household annually. Total energy expenditures during a year cost these homeowners about $1,600 . Energy efficiency improvements that make a home 20 percent more efficient-a conservative estimate for many green homes-could significantly reduce a homeowner's annual utility bill expenses.
As the cost to heat and cool a home becomes more unpredictable, it is advantageous to every homeowner to be "insulated" from inevitable utility bill increases. As with all aspects of these guidelines, the greatest improvements result from a "whole systems" approach. Energy performance does not end with increased R-values, the use of renewable energy, and or more efficient heating and air conditioning equipment. Rather, there needs to be a balance between these features and careful window selection, building envelope air sealing, duct sealing, and proper placement of air and vapor barriers from foundation to attic to create a truly high-performance, energy-efficient home that is less expensive to operate and more comfortable to live in than a conventionally-constructed home.
The mean per capita indoor daily water use in today's homes is slightly over 64 gallons. Implementing water conservation measures can reduce usage to fewer than 45 gallons.
Green homes often conserve water both indoors and out. More efficient water delivery systems indoors and native and drought-resistant landscaping choices outdoors can help prevent unnecessary waste of valuable water resources.
Healthy indoor environments attract many people to green building. After energy efficiency, the quality of a home's indoor air is often cited as the most important feature of green homes.
An increase in reported allergies and respiratory ailments and the use of chemicals that can off-gas from building materials have contributed to a heightened awareness of the air we breathe inside our homes. Even though there is no authoritative definition of healthy indoor air, there are measures that can mitigate the effects of potential contaminants including: controlling the source, diluting the source, and capturing the source through filtration.
Improper or inadequate maintenance can defeat the designer's and builders best efforts to create a resource-efficient home. For example, homeowners often fail to change air filters regularly or neglect to operate bath and kitchen exhaust fans to remove moist air. Many homeowners are unaware of the indoor environmental quality impact of using common substances in and around the house such as pesticides, fertilizers, and common cleaning agents. By providing homeowners with a manual that explains proper operation and maintenance procedures, offers alternatives to toxic cleaning substances and lawn and garden chemicals, and points out water-saving practices, a builder can help assure that the green home that was so carefully built will also be operated in an environmentally responsible manner.
The Built Green Philosophy (Excerpt from The Built Green Website)
WoodRidge Custom Homes and our subcontractors are committed to provide sustainable housing in Kittitas County. Built Green® homes are designed to provide homeowners with comfortable, durable, environmentally friendly homes that are cost-effective to own and operate. These resource-efficient homes are crafted to exceed building codes and provide homeowners with years of healthy, quality living, while protecting the precious Northwest environment.
Built Green® is an environmentally-friendly, non-profit, residential building program developed in partnership with the Central Washington Home Builders Association, Washington State Department of Ecology, and other agencies in Washington State. This website provides consumers with easy-to-understand rating system, which quantifies environmentally friendly building practices for new home construction. Information for communities, remodeling and multifamily development units will be available in the future.
The Central Washington Built Green® program was developed using the National Association of Home Builders National Green Building Standard™. 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 initiated a process for the development of an American National Standards Institute (ANSI) standard for green home building construction practices. The entire process, from the formation of a consensus committee to public review and final ANSI approval, is expected to be completed by February of 2008. After completion of the ANSI process, the standard will be promulgated as a joint publication between NAHB and the ICC. Central Washington Built Green Association is currently the only program in the State of Washington to use the Draft National Green Building Standard™.