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What is Green Building? |
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What is Green Building?
Green buildings are sited, designed, constructed, and operated to enhance the well-being of their occupants and support a healthy community and natural environment.
In practical terms, green building is a “whole-systems” approach to building that includes:
* Using sun and site to the building's advantage for natural heating, cooling, and daylighting
* Landscaping with native, drought-resistant plants and water-efficient practices
* Building quality, durable structures
* Reducing and recycling construction and demolition waste
* Insulating well and ventilating appropriately
* Incorporating durable, salvaged, recycled, and sustainably harvested materials
* Using healthy products and building practices
* Using energy-efficient and water-saving appliances, fixtures and technologies
When implemented holistically, these strategies serve to preserve our environment for future generations by conserving natural resources and protecting air and water quality. They provide benefits for us today by increasing comfort and well-being and helping to maintain healthy air quality. Finally, green building strategies are good for everyone's pocketbook by reducing maintenance and replacement requirements, reducing utility bills and lowering the cost of home ownership, and increasing property and resale values.
Energy Efficiency
Improved comfort and lower energy bills
New houses in California must be built to the most stringent energy code in the country, but given the state’s projected population growth, even this may not be enough to keep demand for energy in check. Generation and use of energy are major contributors to air pollution and global climate change. With homes accounting for roughly 31% of the electricity consumed in the state, it is clear that homebuilders have a significant role to play in helping our society address energy-related concerns now and in the coming decades.
Energy efficiency is the cornerstone of every green home. Improving energy efficiency and using renewable energy sources are effective ways to reduce the potential of energy supply interruptions, improve air quality, reduce the impacts of global warming, and slow the rate at which we need to build new power plants.
Energy efficiency also makes good sense for homeowners: an energy-efficient house saves money by reducing utility bills year after year, and provides other valuable benefits. Better insulation, for example, reduces uncomfortable drafts, and double-pane windows make for a quieter home.
Examples:
* Passive solar heating, overhangs on south windows, deciduous trees on west and south
* Upgraded insulation, SIPs, advanced air infiltration reduction practices (air sealing), Low-E double-pane windows
* Compact fluorescent lighting, low energy-using major appliances
* High-efficiency furnace or zoned, hydronic radiant heat; Tankless water heater
* Whole house fan, solar attic fan
* Solar water heating, photovoltaic system (solar panels), wind turbines
Indoor Air Quality
Safe, pleasant and healthy homes
On average, Americans spend 90% of their time indoors, yet the air in new homes can be ten times more polluted than outdoor air, according to the U.S. Environmental Protection Agency. Children are particularly vulnerable when it comes to air pollution. A report in the New England Journal of Medicine states that 40% of children will develop respiratory disease, in part due to the chemicals in their homes.
A common source of indoor air pollution is the offgassing of chemicals found in many building materials. Kitchen cabinets, countertops, shelving and furniture may be made from particleboard or medium density fiberboard. These pressed-wood products are typically made with adhesives that release urea formaldehyde— a known human carcinogen—into the home for years after installation. Also, many paints, floor finishes, adhesives and sealants emit unhealthy volatile organic compounds (VOCs). That “new house smell” is a telltale sign that there are harmful chemicals in the indoor environment.
Fortunately, the building products industry is responding to these indoor pollution problems by developing safer products, including low-VOC paints, cleaners and adhesives. These products are now commonly available from most major suppliers at costs comparable to conventional products. California also now has specifications available for some materials to assure that they are low emitting and safe.
Poor indoor air quality is also often caused by biological contaminants, such as mold that grows as a result of moisture infiltration due to inadequate ventilation, poor design and maintenance, and other factors. Dust, another major source of air pollution inside homes, can be reduced by installing permanent front door walk-off mats and by using hard surface flooring materials such as natural linoleum, bamboo, wood or wood alternatives, or concrete.
Examples:
* Low or no-VOC paint, wood finishes, & adhesives; avoid products with added formaldehyde
* Mechanical ventilation system, heat recovery ventilation unit, sealed-combustion furnace and water heater
* Range hood and bath fans vent to outside, bath fans automatically controlled with a timer or humidistat
* No wood-burning fireplace, or retrofit wood-burning fireplace with EPA certified wood stoves/inserts
Resource Conservation
Wise resource use for future generations
Conventional building construction and operation consumes large quantities of wood, water, metals, fossil fuels and other natural resources. Even though the majority of the materials used to build a home are put to good use, vast quantities of resources are wasted. In fact, building an average 2,000-sq. ft. house produces about 7,000 pounds of waste.
Much of this waste is avoidable. Careful management of the construction process makes a big difference. There are also many well-established homebuilding practices that help protect natural resources. For example, advanced framing techniques can substantially reduce lumber requirements without compromising structural integrity. Using engineered lumber and wood products certified by the Forest Stewardship Council can help protect old-growth forests.
There are many effective building strategies that conserve natural resources, as well as provide benefits such as cost savings. These include using durable products such as roofing materials with 40- or 50-year warranties, and specifying recycled-content products that divert waste from landfills. Recycled-content decking, reclaimed lumber and other products put waste to good use, while providing quality and durability that often exceed conventional materials. For example, decking materials made of recycled plastic mixed with wood waste fibers can last up to five times longer than wood decking, and never needs to be treated or painted.
Examples:
* Reuse/recycling of C&D (construction & demolition) waste
* High-volume recycled flyash in concrete (min. 25%)
* Reclaimed lumber, flooring, millwork, and other reused or salvaged materials
* FSC-Certified wood, engineered lumber, Advanced Framing techniques
* Recycled-content decking, ceramic tiles, glass tiles or counters, carpet, etc.
* Rapidly renewable flooring: cork, linoleum, bamboo, natural fiber carpet
Water Conservation
Protection and conservation of water supplies
Water is another critical resource. California residences use 5.6 million acre-feet of applied water annually. Our prosperity and ability to meet the needs of our growing population hinge on having adequate supplies of clean, fresh water. Homes built and landscaped to use water wisely make a tremendous contribution to protecting our shared resources. An added benefit is lower expenses for the homeowner. Today’s builders can take advantage of a new generation of cost-effective, high efficiency appliances and landscape water management systems.
Examples:
* Ultra-low flush or dual-flush toilets, fixtures with below standard flow rates (showers<2.5gpm, faucets<2.2gpm)
* Grey water system, rainwater harvesting system, low-water landscaping, native landscaping, high efficiency irrigation system, smart irrigation control, no irrigation
* Living “green” roof, stormwater management (e.g. bio-swales, permeable paving)
Source: Builditgreen.org
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