Monday, January 10, 2011

"The greenest building is the one that's already been built"

Coined by Carl Elefante, we hear this phrase a lot from preservationists (myself included) about how our historic buildings are inherently 'green.' Preservationists have literally been touting this for decades, long before the 'green' movement became all the rage.  I'll admit, I even have a bumper sticker that says "Historic Preservation: The Ultimate Recycling." But what does this mean?

There is a ton of literature and data out there that supports the relationship between historic properties and sustainability, and it can sometimes be daunting to sort through all of it.  I thought I would use this post as an opportunity to provide some useful links and distill some of the research into the basics for those of you who are new to the field of historic preservation:

- Embodied Energy: Historic buildings contain within them a form of energy called "Embodied Energy," meaning the energy it took to originally construct the building, manufacture the materials that form its structure, transport those materials, etc. By demolishing a historic building to build a new 'green' facility, you essentially waste all of the embodied energy which on average is not recouped by the new 'green' facility for at least 50 years.

- Reuse of Materials: Our existing buildings, many of them being historic, act as a very important renewable resource. By recycling our built environment, we cut back considerably on demolition and construction waste piling up in landfills. Additionally, we conserve precious natural resources that would otherwise be used in new construction or development.

- Energy Efficiency: Contrary to popular opinion, historic buildings can be very energy efficient due to their innate architectural characteristics. Some of these features include high quality construction (solid brick walls for greater thermal mass), passive heating and cooling systems such as transoms, awnings and roof overhangs, and large and plentiful windows found in many historic buildings, providing natural daylighting and less need for artificial light. Also, features such as operable wood sash windows were built to be repaired rather than replaced, and their old dense wood will last for a very long time if kept painted and maintained. Non-sustainable vinyl replacement windows are a petroleum-based product, can off-gas toxic substances into the air, and will only last a small fraction of the lifetime of an older wood window. Weatherizing, installing storm windows, using heavy window treatments, and installing insulation in the attic and basement are better ways to minimize heat loss in an old home.

- Historic Site Setting: many historic buildings usually have some old growth trees and mature landscaping, which, equals better natural cooling during the summer months.

- Smart Growth: Historic buildings are often located in historic districts, which, in many cases are walkable, mixed use communities. Historic districts contain and promote high density building practices, conserving green space and reducing traffic congestion and carbon emissions.

Be sure to check out the blog, The Greenest Building is the One Already Built, for more in depth information, resources, articles and links!

These are just a few of the ways historic buildings are inherently sustainable, and I've barely touched on the partnership between the green movement and historic preservation. To learn more about this topic, The National Trust has some great information located here: . Also check out the National Institute of Building Sciences Whole Building Design Guide  as well as

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