What is Sustainable Design?
See
also: Basic Sustainable Design Principles
Energy
Efficiency
Material Efficiency
Water Efficiency
Regional Design
Overview of general features/components
Sustainability often is defined as meeting the
needs of the present without compromising the ability of future generations to meet their
own needs. A growing number of people are
committed to reaching this goal by modifying patterns of development and consumption to
reduce demand on natural resource supplies and help preserve environmental quality. Achieving greater sustainability in the field of
construction is particularly important, because building construction consumes more energy
and resources than any other economic activity. Not
only does a home represent the largest financial investment a family is likely to make,
but it also represents the most resource- and energy-intensive possession most people will
ever own. Making homes more sustainable,
then, has a tremendous potential to contribute to the ability of future generations to
meet their own needs.
Sustainable housing design is a
multifaceted concept, embracing:
 Only a holistic approach to
design— one that considers and addresses each of these facets—can truly claim to
provide a sustainable house. Remember that even
if you can’t implement a holistic approach anything you do to improve sustainability
is better than nothing at all. Fortunately green building programs,
guidelines and the recommendations and references of the HomeASTA program are available to
make sustainable design attainable for affordable housing.
Affordability
There is a common perception that
sustainable building is more expensive than conventional building. This is not necessarily the case. In fact, some of the principles of sustainable
design inherently tend to reduce costs of developments, if not of individual homes. Sustainable development’s emphasis on
limiting infrastructure and materials use helps contribute to affordability during the
construction of a project by eliminating some costs altogether. In the longer term, sustainable design’s
principles of energy and water efficiency and material durability help make a home
affordable for the occupant to operate over the building’s entire lifetime.
Taking a broader approach,
sustainable building can be viewed as the only truly affordable housing, in an
environmental sense. Because building
sustainably consumes less energy and resources, and produces less pollution, it has a
lower environmental and social cost than conventional modern housing.
Finally, although numerous high-end
custom homes have been built incorporating some of the principles of sustainable design,
there also are shining examples of affordable housing that embodies sustainability. Habitat for Humanity, nonprofit and for-profit
developers, and governmental housing authorities all have successfully completed homes
with sustainable design features and materials at affordable costs.
Marketability
Market surveys repeatedly have shown
that home buyers appreciate some of the characteristics of sustainable design, such as
energy efficiency and good indoor air quality, enough to pay extra for them. Many people also have defined themselves as
environmentalists and proclaimed their commitment to environmental stewardship and the
purchase of environmentally preferable products. The
increase nationwide in local green building programs and media coverage of green building
indicates that sustainable design is a growing market sector. Additionally, consistently brisk home sales in
green developments provide evidence of the marketability of sustainable design. For more information, see Building Green in a Black and White World.
National and regional lending
institutions have recognized the benefits that energy efficiency and a location near
public transportation can have for homebuyers and have developed special lending programs
for homes with these features. This
endorsement of some of the principles of sustainable design by major housing lenders
provides a strong indication of market support.
Appropriate Design
 Sustainable home designs are
suited to both the place where they are built and the functions they will serve. An appropriate design is responsive to the
regional climate, the microclimate of the site, and the terrain. Using locally available
building materials also aids a design in being appropriate to its place. In addition, an appropriate design has a style
respectful of its cultural surroundings – harmonizing with neighboring houses and
contributing to preservation of the community’s cultural heritage and neighborhood
value.
A home design should not only be
appropriate to its environment, but also functional.
For example, sustainable houses are designed to be space- efficient. Designing and building smaller houses is the most
certain way to achieve greater energy and resource efficiency. Yet the functionality of a house shouldn’t be
compromised by reducing its size. Fortunately,
well-designed smaller homes can serve their occupants’ needs much more effectively
than large dwellings with thoughtlessly tacked-on extra space. Space-efficient designs eliminate wasted hallway
space, while considering how traffic flows will affect the use of rooms. Long views in an open floor plan can help smaller
houses to “live large.” Multipurpose
spaces and built-in storage help make the most of every available space. Some new design concepts even include movable
walls to allow a space to change with a family’s changing needs. Across the country, many people are recognizing
that good design is much more appealing and functional than simply adding more square
footage—and it costs less to maintain, heat and cool.
Resource
Efficiency
Sustainable design revolves around
the efficient application of resources in residential construction, whether those be the
material resources used in construction of a home, or the material and water resources
used in operation and maintenance of a home. In
sustainable design, the resource consumption of the average home is cut, sometimes
dramatically, both in terms of materials used and materials wasted. Resource efficiency can involve using fewer
materials overall in construction, but it can also lead to the choice of more resource
efficient building products over conventional alternatives for the materials that are
used. These resource efficient materials can
generally be defined as materials which are more—rather than less—abundant,
which cause less environmental impact in their production, which are recycled or reused,
or which contribute substantially to the improved performance or longevity of the building
as a whole.
Energy
Efficiency
Energy efficiency in a home considers
both the rate of energy use and the source of the energy that is used. Sustainable design produces homes that use less
energy to operate because they feature efficient designs, materials and systems. The most sustainable houses have highly efficient
heating, cooling, ventilation, lighting systems, and appliances. In addition, these sustainable homes are built of
energy-efficient materials carefully installed to prevent the loss of conditioned (i.e.,
heated or cooled) air.
Including energy efficiency measures
may cost more at the time of construction, but the investment usually pays back quickly
through savings in operating the house. In
the long run, energy-efficient housing saves money, prevents pollution, and conserves
non-renewable energy resources.
The sustainability of energy
conservation is augmented by obtaining energy from renewable sources. Passive solar energy is the most sustainable form
of heating. Similarly, shading and natural
ventilation are the most sustainable and low-cost methods of cooling a home, and daylight
is an effective means of lighting. These
methods are completely renewable and require a minimum of equipment. Solar photovoltaics, wind and hydro power also use
renewable energy sources, but require more expensive initial equipment investments.
Durability
 Sustainable design incorporates
durable materials, properly assembled to comprise a durable system. Using durable materials avoids the expense and
resource consumption of materials that fail sooner, requiring replacement and potentially
damaging other systems and components. The
need to dispose of failed materials also is avoided by using durable
materials. Furthermore, durable materials
also should require less time and expense for maintenance.
Although durable materials may have a higher initial cost than short-lived or
disposable materials, they will save both money and resources over the long run.
An important aspect of durability is not only
purchasing durable materials, but also making certain that they are properly installed so
that they can perform to their full potential. Construction
details that prevent moisture and air infiltration and insect or weather damage can be the
key to the longevity of a dwelling.
Comfort
 Too
often, people who aren’t familiar with the idea of sustainable design equate it with
uncomfortable, odd-looking structures. In
reality, homes that embody holistic sustainable design are warm in winter, cool in summer,
well-lit, well-ventilated, attractive, and truly functional. In addition, sustainably designed homes require less
energy and maintenance. In commercial design,
companies that have constructed sustainable offices, stores, and factories find that
worker productivity increases as a result of these new buildings. Also, sustainable design includes consideration of
indoor air quality, a building attribute that promotes both comfort and health.
Health
Promoting construction worker and
home occupant health is a strong component of sustainable design. Sustaining the health of
construction site workers involves choosing less-toxic material alternatives and providing
worker training in specialized installation procedures. There are several strategies that
are important for addressing the health of home occupants over the long term. These include designs that provide for foundation
radon venting in areas where radon is a concern. Also,
choosing less toxic building materials and interior finishes, and providing for home
ventilation, will help contribute to healthy indoor air quality. Another important consideration for occupant
health is avoiding appliance and HVAC system backdrafting by selecting sealed-combustion
units, and providing appropriate venting. On
another front, sustainable buildings feature designs, material installation, and
ventilation that prevent moisture from accumulating within building walls or roofs where
it can cause life-threatening molds and lead to structural damage from rot.
Next Section:
Basic Sustainable Design Principles
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