Monday, April 14, 2008

Save the buildings, save the world

[Source: Richard Moe, New America Media] -- Historic preservation has always been the greenest of the building arts because it necessarily involves the conservation of energy and natural resources. Now it’s time to make sure everyone knows it. It’s all about sustainability. According to the Environmental Protection Agency (EPA), transportation accounts for just 27 percent of America’s greenhouse gas emissions, while 48 percent – almost twice as much – is produced by the construction and operation of buildings. Nearly half the greenhouse gases Americans send into the atmosphere is from our buildings. More than 10 percent of the entire world’s greenhouse gas emissions is from American buildings. Historic preservation must be a key component of any effort to promote sustainable development. The challenge is to help people understand that preservation is environmentally, as well as economically, sustainable.

Buildings are embodied energy

The retention and reuse of older buildings is an effective tool for the responsible, sustainable stewardship of our environmental resources. Buildings are vast repositories of energy. It takes energy to manufacture or extract building materials, more energy to transport them to a construction site, still more energy to assemble them into a building. If the structure is demolished and land-filled, the energy locked up in it is wasted.

  • According to the Advisory Council on Historic Preservation, about 80 billion British Thermal Units (BTUs) of energy are embodied in a typical 50,000-square-foot commercial building, the equivalent of 640,000 gallons of gasoline. If you tear the building down, all of that embodied energy is wasted.

  • Constructing a 50,000-square-foot commercial building releases about the same amount of carbon into the atmosphere as driving a car 2.8 million miles. Demolishing it creates nearly 4,000 tons of waste.

  • Since 70 percent of the energy consumed over a building’s lifetime is used in operating the building, some people argue that the energy used in demolishing an older building and replacing it is quickly recovered through the increased energy efficiency of the new building – but that’s simply not true. Recent research indicates that even if 40 percent of the materials are recycled, it takes approximately 65 years for a green, energy-efficient new office building to recover the energy lost in demolishing an existing building.

[Note: To read the full article, click here. Photo source: Michael Lundgren. Phoenix Towers, Phoenix.]