Tuesday, December 9, 2008

Historic Preservation Is Sustainable Living

By: Jason Yots

The greenest building is the one that is already built.

For decades, the historic preservation and environmental movements advanced on parallel tracks. Although some ideas from both efforts overlapped, those similarities did not translate into effective coordination or collaboration. Recently, however, some historic preservation experts have successfully demonstrated that preservationists and environmentalists share a common mission: promoting sustainable living. For preservationists, this fresh approach adds a compelling new counterpoint to our efforts to promote historic preservation. For communities, this concept affords new economic development strategies and, more importantly, delivers an affordable means to redesign themselves as sustainable living environments.

In this entry, we will examine some of the ways in which historic preservation efforts are environmentally friendly and contribute to sustainability.

Embodied Energy? Is That A New Sports Drink?

The concept of embodied energy is perhaps best introduced by comparing it to operating energy. Operating energy is the energy a building will use in the future for things like climate control and illumination. But operating energy is only half of the story of a building’s energy use. The rest of the story involves “embodied energy”, the amassed energy that was required to extract, process, manufacture, transport and install building materials for a building.
Recent research on embodied energy suggests that placing embodied energy into the energy efficiency equation means that a new, energy efficient commercial building will not even start saving energy for 40 years. Furthermore, if the new building replaces an older building that is demolished, the break-even period spikes to as long as 65 years. Ironically, most of today’s construction methods and materials are not even designed to last that long. In the big picture, a new “green” building that replaces an existing building operates at an energy deficit for its entire useful life.

That Drafty Old Building Is Not As Drafty As You Think
When promoting historic preservation, we often hear the adage that new buildings are inherently more efficient than older buildings. This just isn’t true. According to the US Energy Information Administration, commercial buildings constructed prior to 1920 have an average energy consumption of about 80,127 BTUs per sf. For more efficient buildings built since 2000, that number is about 79,703 BTUs. For less efficient buildings built since 2000, that number spikes to about 100,000 BTUs. Moreover, since builders couldn’t entirely control indoor climates 100 years ago, many older buildings may in fact be more energy efficient than their newer counterparts because they were designed, sited, built and ventilated to maximize the benefits, and minimize the harshness, of the local climate.

Recycle Your Cans And Your Building
We’ve already discussed the embodied energy impact of demolishing a building, but the direct impact on the environment is perhaps even more compelling. On a micro scale, historic preservation expert Donovan Rypkema estimates that demolishing a small commercial building negates the environmental benefit of recycling 1,300,000 aluminum cans. On a more macro level, the Brookings Institution projects that Americans will demolish and replace nearly 82,000,000,000 (yes, billion) square feet of building space between now and 2030. The resulting debris would fill 2,600 football stadiums and the energy expended to demolish older buildings and build replacements during that period would power the state of California for ten years.

Functional Obsolescence? I’d Like A Second Opinion
When my old computer no longer could run a current operating system, it became functionally obsolete; it was unable to meet my new demands as a user. For a building, functional obsolescence sets in when the building no longer meets market demands. But when a building is initially deemed to be obsolete, our knee-jerk reaction should not be “Demolish!”, it should be “Re-use?” Until all reasonable re-use options are explored, a building should not be doomed to obsolescence. As my dad would say, look no further than the Silophone (http://www.silophone.net/) in Montreal for an example of the multitude of potential new uses for a seemingly “obsolete” structure.


Select Bibliography:
1. Curtis, Wayne, A Cautionary Tale, Preservation (Jan/Feb 2008).
2. Lawniczak, Joe, Historic Preservation and Sustainable Development, Wisconsin Main Street News (Fall 2008).
3. Rypkema, Donovan, The Economics of Historic Preservation (1994).
4. Rypkema, Donovan, "Sustainability and Historic Preservation" (Speech delivered to the Heritage Society of Austin, November 9, 2007).

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