But what does this concept mean? Aren’t new green buildings the way of the future?
According to TAE, “The Pew Center on Global Climate Change estimates that 43 percent of carbon emissions in the United States are attributable to energy used in residential, commercial and industrial buildings, making the building sector the largest source of greenhouse gases in America. This figure does not even include the energy required to build new structures or to demolish established structures.”
As much as new green buildings are the boon to our continued interest in sustainable development, there is a great deal of misunderstanding in what is lost when older buildings are demolished in the name of progress. The main loss is what is known as “embodied energy,” the concept encompassing “the sum of all of the efforts in the building of the structure itself: the harvesting of organic resources plus the manufacturing development (making those materials into building materials), transportation and the building itself,” according to Lindsey Wallace, donor relations assistant for the TAE. “With new construction, you have to make all that, and it creates a lot of waste.”
The crucial element in the loss of embodied energy is that it cannot be regained. Granted, building salvage businesses are alive and well, but on the whole, a great deal of energy, carbon emissions, materials, time and labor are gone when a building is taken down.
According to Richard Moe, president for the National Trust for Historic Preservation, “Demolishing a 50,000 square foot building creates 4,000 tons of waste, enough to fill 26 box cars – a train one-quarter mile long.” Additionally, “Constructing a new 50,000 square foot building releases as much carbon as driving a car 2.8 million miles.”
TAE also reports, “The Brookings Institution estimates that, at current rates, one third of the existing building stock in the United States will be demolished in the next 25 years. The refuse from construction, primarily from demolition, represents approximately 25 percent of the waste added to our landfills each year.”
New Vs. Old
“We’re not completely forgetting that new construction is ‘green,’ but it should be pointed out that some studies show that the rehab of a historic structure achieves the same energy efficiency,” said Heather Massler, director of operations and stewardship for TAE. When it comes to the environmental benefits of rehabilitating and retrofitting older structures, you may be surprised at your energy savings.
According to Moe, “It takes approximately 65 years for a green, energy-efficient building to recover the energy lost in demolition of an existing building even if 40 percent of the building materials from the demolition are recycled.”
A classic example of a reused, rehabilitated building is when an old factory (for example) is converted into loft apartments. Rather than tearing down the older structure and replacing it with a new high rise, the integrity of the structure itself remains (many people, in fact, enjoy the scuffed, burned or nicked floors and walls of buildings like these for their “character”) and the resources used to complete it in the first place are intact.
Massler also pointed out that if you’re looking to update your existing home, reaching for older materials is also a savings in energy. “Your choices are about consumption. Can I live with what I have, or does this really need to be replaced? Why rip out old floors to replace them with new bamboo? Old buildings usually have really durable materials, and there’s a whole salvage world out there.”
One With Nature
Another important consideration for older buildings is their use of the site on which they were constructed, or as Wallace put it, “taking advantage of how people have built for thousands of years.”
“Historic buildings already use the natural resources as much as possible [...] Several studies have shown that with proper repair and upkeep, they can be just as energy efficient,” said Massler.
Historic buildings typically have high ceilings, transoms and large windows for light and ventilation. Site selection and placement on the site, as well as porches and the use of landscaping, contribute to the efficient use of energy, according to TAE.
“People used to think about the site more, because modern conveniences weren’t already in place,” said Massler.
Along these lines, TAE reports that, “Data from the U.S. Energy Information Agency indicates that structures built prior to 1920 are more energy-efficient than those built through the year 2000, when the concept of sustainability began to take hold.”
Additionally, the General Services Administration estimates that the utility costs for historic buildings in its inventory are 27 percent less than for modern structures.
Economic Centers
U.S. General Services Administration (GSA) found that utility costs for historic buildings were 27% lower than for more modern buildings. - Preservationnj.wordpress.com
Who knew older buildings used less average energy than their modern counterparts? Photo: Preservationnation.org
“As economist Donovan Rypkema has pointed out, preserving a building is equal to preserving land,” said Wallace. “When preserving buildings in an urban center, you’re discouraging sprawl. The focus on building rehab is about reinvesting in urban centers.”
“When we think of sustainable development, with preservation and rehabilitation, it also speaks to culture and economic sustainability which isn’t talked about as much, but is still as important,” said Massler. “If you are rehab-ing any building in a city, the labor costs are a lot more than the actual materials, helping provide jobs. For example, Rypkema said that if you spend more money on the labor, you’re spending more money for the economy, because the laborer will spend the money again.”
“The preservation community has been advocating for federal tax credits for rehab-ing for exactly this issue, especially for retrofits – using resources already there, specialized labor that pays better, they put people back to work,” said Wallace.
LEEDing on
The National Trust for Historic Preservation and a number of other organizations, are working with the U.S. Green Building Council (the council responsible for the LEED program) to incorporate more preservation aspects in LEED certification. In fact, the new 2009 LEED Green Building Rating Systems will reflect the sustainable benefits of historic preservation.
But what can you do in the meantime? Even if you don’t have a big preservation project in the works, little steps in your own home still make a big difference. According to Wallace, “small efforts like weather stripping, really do add to your energy savings.” Massler also added that, “Most people want to be green or want to help out in whatever way they can. Just thinking about it and being aware is the first step.”
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