The environmental
impact of buildings
Buildings have a profound effect on the environment,
which is why green building practices are so important to reduce and perhaps
one day eliminate those impacts.
In the United States, buildings account for:
- between 40 and 49% of total energy use
- 25% of total water consumption
- 70% of total electricity consumption
- 38% of total carbon dioxide emissions
However, the environmental impact of buildings is
often underestimated, while the perceived costs of building green are
overestimated. A recent survey by the World
Business Council for Sustainable Development finds that green costs are
overestimated by 300%, as key players in real estate and construction estimate
the additional cost at 17% above conventional construction, more than triple
the true average cost difference of about 5%.
Green building
practices
Green building brings together a vast array of
practices and techniques to reduce and ultimately eliminate the impacts of
buildings on the environment and human health. But effective green buildings
are more than just a random collection of environmental friendly technologies.
They require careful, systemic attention to the full life cycle impacts of the
resources embodied in the building and to the resource consumption and
pollution emissions over the building's complete life cycle.
On the aesthetic side of green
architecture or sustainable
design is the philosophy of designing a building that is in harmony with
the natural features and resources surrounding the site. There are several key
steps in designing sustainable buildings: specify 'green' building materials
from local sources, reduce loads, optimize systems, and generate on-site
renewable energy.
Building materials typically considered to be 'green'
include rapidly renewable plant materials like bamboo and straw, lumber from
forests certified to be sustainably managed, dimension stone, recycled stone,
recycled metal, and other products that are non-toxic, reusable, renewable,
and/or recyclable. Building materials should be extracted and manufactured
locally to the building site to minimize the energy embedded in their
transportation.
Low-impact building materials are used wherever
feasible: for example, insulation may be made from low VOC emitting materials
such as recycled
denim or cellulose
insulation, rather than the building
insulation materials that may contain carcinogenic or toxic materials such
as formaldehyde. To discourage insect damage, these alternate insulation
materials may be treated with boric
acid. Organic or milk-based paints may be used. However, a common fallacy
is that "green" materials are always better for the health of
occupants or the environment. Many harmful substances (including formaldehyde,
arsenic, and asbestos) are naturally occurring and are not without their
histories of use with the best of intentions. A study of emissions from
materials by the State of California has shown that there are some green
materials that have substantial emissions whereas some more
"traditional" materials actually were lower emitters. Thus, the
subject of emissions must be carefully investigated before concluding that
natural materials are always the healthiest alternatives for occupants and for
the Earth.
Architectural salvage and reclaimed materials are
used when appropriate as well. When older buildings are demolished, frequently
any good wood is reclaimed, renewed, and sold as flooring. Any good dimension
stone is similarly reclaimed. Many other parts are reused as well, such as
doors, windows, mantels, and hardware, thus reducing the consumption of new
goods. When new materials are employed, green designers look for materials
that are rapidly replenished, such as bamboo,
which can be harvested for commercial use after only 6 years of growth, or cork
oak, in which only the outer bark is removed for use, thus preserving the
tree. When possible, building materials may be gleaned from the site itself;
for example, if a new structure is being constructed in a wooded area, wood
from the trees which were cut to make room for the building would be re-used
as part of the building itself.
To minimize the energy loads within and on the
structure, it is critical to orient the building to take advantage of cooling
breezes and sunlight. Daylighting with ample windows will eliminate the need
to turn on electric lights during the day (and provide great views outside
too). Passive
Solar can warm a building in the winter but care needs to be taken to
provide shade in the summer time to prevent overheating. Prevailing breezes
and convection currents can passively cool the building in the summer. Thermal
mass stores heat gained during the day and releases it at night minimizing
the swings in temperature. Thermal mass can both heat the building in winter
and cool it during the summer. Insulation is the final step to optimizing the
structure. Well-insulated windows, doors, and ceilings
and walls help reduce energy loss, thereby reducing energy usage. These
design features don't cost much money to construct and significantly reduce
the energy needed to make the building comfortable.
Optimizing the heating and cooling systems through
installing energy efficient machinery, commissioning,
and heat recovery is the next step. Compared to optimizing the passive heating
and cooling features through design, the gains made by engineering are
relatively expensive and can add significantly to the projects cost. However,
thoughtful integrated design can reduce costs for example, once a building
has been designed to be more energy-efficient, it may be possible to downsize
heating, ventilation and air-conditioning (HVAC) equipment, leading to
substantial savings. To further address energy loss hot
water heat recycling is used to reduce energy usage for domestic water
heating. Ground
source heat pumps are more energy efficient then other forms of heating
and cooling.
Finally, onsite generation of renewable energy
through solar
power, wind
power, hydro
power, or biomass
can significantly reduce the environmental impact of the building. Power
generation is the most expensive feature to add to a building.
Good green architecture also reduces waste, of
energy, water and materials. During the construction phase, one goal should be
to reduce the amount of material going to landfills. Well-designed buildings
also help reduce the amount of waste generated by the occupants as well, by
providing onsite solutions such as compost bins to reduce matter going to
landfills.
To reduce the impact on wells or water treatment
plants, several options exist. "Greywater",
wastewater from sources such as dishwashing or washing machines, can be used
for subsurface irrigation, or if treated, for non-potable purposes, e.g., to
flush toilets and wash cars. Rainwater collectors are used for similar
purposes.
Green building often emphasizes taking advantage of renewable
resources, e.g., using sunlight through passive
solar, active
solar, and photovoltaic
techniques and using plants and trees through green
roofs, rain
gardens, and for reduction of rainwater run-off. Many other techniques, such as using packed gravel for parking lots instead of
concrete or asphalt to enhance replenishment of ground water, are used as
well.
Green building
worldwide
Standards and
ratings
Many countries have developed their own standards of
energy efficiency for buildings.
- Code
for Sustainable Homes, United Kingdom
- EnerGuide
for Houses, Canada (energy retrofits & up-grades)
- EnerGuide
for New Houses, Canada (new construction)
- House
Energy Rating, Australia
- DGNB, www.dgnb.de, Germany
- One Planet Living, www.biogregional.uk, WWF
International
- Green Building Council, www.gbcaus.org, Australia
- BCA Green MArk, www.bca.gov.sg/green mark
buildings.html, Singapore
- BRIAM, United Kingdom
- CASBEE, Japan
- Green Globe, www.greenglobes.com, USA, Canada
- Leadership
in Energy and Environmental Design (LEED), multiple countries
- EEWH,
Taiwan
Australia
There is a system in place in Australia
called First Rate designed to increase energy efficiency of residential
buildings. The Green Building Council of Australia (GBCA) has developed a
green building standard known as Green
Star.
In Adelaide,
South Australia, there are at least two different projects that incorporate
the principles of Green building. The Eco-City development is located in
Adelaide's city centre and the Aldinga
Arts Eco Village is located in Aldinga.
Guidelines for building developments in each project are outlined in the
bylaws. The bylaws include grey water reuse, reuse of stormwater, capture of
rainwater, use of solar panels for electricity and hotwater, solar passive
building design and community gardens and landscaping.
Melbourne
has a rapidly growing environmental consciousness, many government subsidies
and rebates are available for water tanks, water efficient products (such as
shower heads) and solar hot water systems. The city is home to many examples
of green buildings and sustainable development such as the CERES
Environmental Park. Another one is EcoLinc in Bacchus Marsh. Two of the most prominent examples of
green commercial buildings in Australia are located in Melbourne 60L and Council House 2 (also known as CH2).
The most recent building to receive the 6 Green Star
award was in Canberra,
where Australian Ethical Investment Ltd
refurbished an existing office space in Trevor Pearcey House. The total cost
of the renovation was $1.7 million, and produced an estimated 75% reductions
in carbon dioxide emissions, 75% reduction in water usage, and used over 80%
recycled materials.
Canada
Canada has implemented "R-2000" guidelines
for new buildings built after the year 2000. Incentives are offered to
builders to meet the R-2000 standard in an effort to increase energy
efficiency and promote sustainability.
A progression of the R-2000 home program is the EnerGuide
for New Houses service. This service is available across Canada and is
designed to allow home builders and home buyers to build homes that use
significantly less energy than the average homes being built. Some Canadian
provinces are considering mandatory use of the service for all new homes.
In December 2002, Canada
formed the Canada
Green Building Council and in July 2003 obtained an exclusive license from
the US Green Building Council to adapt the LEED rating system to Canadian
circumstances. The path for LEED's entry to Canada had already been prepared
by BREEAM-Canada, an environmental performance assessment standard released by
the Canadian
Standards Association in June 1996. The American authors of LEED-NC 1.0
had borrowed heavily from BREEAM-Canada in the outline of their rating system;
and in the assignment of credits for performance criteria.
- Beamish-Munro Hall at Queen's
University features sustainable construction methods such as high
fly-ash concrete, triple-glazed windows, dimmable fluorescent lights and a
grid-tied photovoltaic array.
- Gene
H. Kruger Pavilion at Laval
University uses largely non polluting, non toxic, recycled and
renewable materials as well as advanced bioclimatic concepts that reduce
energy consumption by 25% compared with a concrete building of the same
dimensions. The structure of the building is made entirely out of wood
products, thus further reducing the environmental impact of the building..
Germany
German developments that employ green building
techniques include:
- The Solarsiedlung (Solar Village) in Freiburg,
Germany, which features energy-plus
houses.
- The Vauban
development, also in Freiburg.
- Houses designed by Baufritz,
incorporating passive solar design, heavily insulated walls, triple-glaze
doors and windows, non-toxic paints and finishes, summer shading, heat
recovery ventilation, and greywater
treatment systems.
- The new Reichstag
building in Berlin,
which produces its own energy.
India
- Main article: Energy
efficient buildings in India
The Confederation of Indian Industry (CII) plays an
active role in promoting sustainability in the Indian construction sector. The
CII is the central pillar of the Indian Green Building Council or IGBC. The
IGBC has licesensed the LEED Green Building Standard from the U.S. Green
Building Council and currently is responsible for certifying LEED-New
Construction and LEED-Core and Shell buildings in India. All other projects
are certified through the U.S. Green Building Council. There are many energy
efficient buildings in India,
situated in a variety of climatic zones.
Israel
Israel has recently implemented a voluntary standard
for "Buildings with Reduced Environmental Impact" 5281, this
standard is based on a point rating system (55= certified 75=excellence) and
together with complementary standards 5282-1 5282-2 for energy analysis and
1738 for sustainable products provides a system for evaluating environmental
sustainability of buildings. United States Green Building Council LEED rating
system has been implemented on several building in Israel including the recent
Intel Development Center in Haifa and there is strong industry drive to
introduce an Israeli version of LEED in the very near future.
Malaysia
The Standards
and Industrial Research Institute of Malaysia (SIRIM) promotes green
building techniques.
New Zealand
The New
Zealand Green Building Council has been in formation since July 2005. An
establishment board was formed later in 2005 and with formal organizational status granted on 1st February 2006. That month Jane Henley was appointed as
the CEO and activity to gain membership of the World GBC began. In July 2006
the first full board was appointed with 12 members reflecting wide industry
involvement. The several major milestones were achieved in 2006/2007; becoming
a member of the World GBC, the launch of the Green Star NZ Office Design
Tool, and welcoming our member companies.
United Kingdom
-
The Association
for Environment Conscious Building (AECB) has promoted sustainable
building in the UK since 1989.
The UK Building
Regulations set requirements for insulation
levels and other aspects of sustainability in building construction.
United States
The United
States Green Building Council (USGBC) has developed The Leadership
in Energy and Environmental Design (LEED) green building rating system,
which is the nationally accepted benchmark for the design, construction and
operation of high performance green buildings.
The Green Building Initiative is a non-profit network
of building industry leaders working to mainstream building approaches that
are environmentally progressive, but also practical and affordable for
builders to implement. The GBI has developed a web-based rating tool called
Green Globes, which is being upgraded in accordance with ANSI procedures.
The United States Environmental
Protection Agency's EnergyStar
program rates commercial buildings for energy efficiency and provides
EnergyStar qualifications for new homes that meet its standards for energy
efficient building design.
In 2005,
Washington
became the first state in the United States to enact green building
legislation.
According to the law, all major public agency facilities with a floor area
exceeding 5,000 square feet (465 mē), including state funded school
buildings, are required to meet or exceed LEED standards in construction or
renovation. The projected benefits from this law are 20% annual savings in
energy and water costs, 38% reduction in waste water production and 22%
reduction in construction waste.
Charlottesville,
Virginia became one of the first small towns in the United States to enact
green building legislation.
This presents a significant shift in construction and architecture as LEED
regulations have formerly been focused on commercial construction. If US
homeowner interest grows in "green" residential construction, the
companies involved in the production and manufacturing of LEED building
materials will become likely candidates for tomorrow's round of private equity
and IPO investing.
