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Sustainable Design Can Save More Than the Environment

Some tactics for making buildings sustainable, primarily involving material specifications and engineering systems design, are important, but often not visible. What is apparent are building geometries and exterior enclosures, clearly the most visible manifestation of sustainability.

Because energy conservation is a major goal of sustainability, and because a building's energy consumption is determined to a great extent by volume and cladding characteristics, architects must still concentrate design attention on building form and facades.

Generally, more compact buildings require fewer materials, which means less energy invested in construction and, with reduced exterior surface, less energy to heat and cool buildings after construction.

At one extreme is the sphere, the most efficient form because its skin-to-volume ratio is lower than any other geometric shape. This suggests that for optimum sustainability, blob-like architecture might be the wave of the future. But blobs are less than ideal for accommodating most building functions or for harmonizing with adjacent structures.

Conversely, geometrically distended, multifaceted or fragmented buildings are the least efficient. They have greatly increased exterior surface area and skin-to-volume ratios, which adds significantly to costs, in dollars and energy, for construction and operation.

Accordingly, rectilinear volumes are more prevalent and practical, since much of the fabricated world is based on straight lines and right angles. Sometimes architects transform rectilinear volumes using circular and spherical geometries -- for instance, the National Museum of the American Indian -- although usually not for reasons of sustainability.

No matter how efficiently configured, a compact form remains aesthetically mute until its exterior walls are composed. And facades continue to offer architects their greatest opportunity for developing new modes of artistic expression based on sustainability-related composition.

Such opportunities are numerous: employ visually diverse cladding materials and textures; control, filter, reflect or transmit daylight to the interior; shade summer sun but admit winter sun to provide heat; cast ever-changing shadow patterns; allow natural ventilation; exploit views to and from the interior; and create overall window and door patterns, juxtaposing transparency and opacity, to animate and impart order to facades.

Yet few of these moves are new. Ancient Greek and Roman builders, Renaissance and Enlightenment architects, and architects of the Modern movement understood these moves long before energy was an issue and long before anyone used the word "sustainability."

Designing for sustainability merely continues an ageless architectural tradition, based on the idea that "necessity is the mother of invention." Thus pursuing sustainable design is not only the ethical and, in the long run, the most economical thing to do, but also the smart thing to do to make buildings look and perform better.

Roger K. Lewis is a practicing architect and a professor of architecture at the University of Maryland.

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