THE IGNORED GREENNESS OF HISTORIC PRESERVASTION

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[From a speech at the National Building Museum]

RICHARD MOE, NATIONAL TRUST FOR HISTORIC PRESERVATION - Up to now, our
approach to life on this planet has been based on the assumption that
"there's plenty more where that came from." With our environment in
crisis, we have to face the fact that there may not be "plenty more" of
anything – except trouble. In the face of that realization, we're
challenged to find a way of living that will ensure the longevity and
health of our environmental, economic, and social resources. . .

The United States is a big part of the problem. We have only 5% of the
world's population, but we're responsible for 22% of the world's
greenhouse gas emissions that are the leading cause of climate change.
Much of the debate on this subject usually focuses on the need to reduce
auto emissions. But according to the EPA, transportation – cars, trucks,
trains, airplanes – accounts for just 27% of America's greenhouse gas
emissions, while 48% – almost twice as much – is produced by the
construction and operation of buildings. . . In fact, more than 10% of
the entire world's greenhouse gas emissions is produced by America's
buildings – but the current debate on climate change does not come close
to reflecting that huge fact. . . 

The retention and reuse of older buildings is an effective tool for the
responsible, sustainable stewardship of our environmental resources –
including those that have already been expended. . .

According to a formula produced for the Advisory Council on Historic
Preservation, about 80 billion BTUs of energy are embodied in a typical
50,000-square-foot commercial building. That's the equivalent of 640,000
gallons of gasoline. If you tear the building down, all of that embodied
energy is wasted.

What's more, demolishing that same 50,000-square-foot commercial
building would create nearly 4,000 tons of waste. That's enough debris
to fill 26 railroad boxcars – that's a train nearly a quarter of a mile
long, headed for a landfill that is already almost full.

Once the old building is gone, putting up a new one in its place takes
more energy, of course, and it also uses more natural resources and
releases new pollutants and greenhouse gases into our environment. Look
at all the construction cranes dotting the Washington skyline, and
consider this: It is estimated that constructing a new
50,000-square-foot commercial building releases about the same amount of
carbon into the atmosphere as driving a car 2.8 million miles.

Since 70% of the energy consumed over a building's lifetime is used in
the operation of the building, some people argue that all 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%
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. And let's face it: Most new
buildings aren't designed to last anywhere near 65 years.  Despite these
surprising statistics and many more like them, we persist in thinking of
our buildings as a disposable – rather than a renewable – resource.

A report from the Brookings Institution projects that by 2030 we will
have demolished and replaced 82 billion square feet of our current
building stock, or nearly 1/3 of our existing buildings, largely because
the vast majority of them weren't designed and built to last any longer.


That much demolition will create a lot of debris. If we didn't recycle
any of the building materials, we'd be left with 5.5 billion tons of
waste. That's enough debris to fill almost 2,500 NFL stadiums. 

How much energy will it take to demolish and replace those buildings?
Enough to power the entire state of California – the 10th largest
economy in the world – for 10 years. On the other hand, if we were to
rehab just 10% of these buildings, we would save enough energy to power
the state of New York for well over a year.

Instead of focusing on generalities, let's look at a specific building –
like the one we're in right now.

It's estimated that the National Building Museum contains about 1.5
million bricks. When you consider how much energy it took to make all
those bricks, plus how much it took to manufacture the other materials,
then transport them to this site and put them all together in this
marvelous structure, the total embodied energy in this building is the
equivalent of nearly 2 million gallons of gasoline. If we assume the
average vehicle gets about 21 miles to the gallon, that means there's
enough embodied energy in this building to drive a car about 42 million
miles.

All of that energy would be wasted if this building were to be
demolished and landfilled. What's more, the demolition itself would
require the equivalent of more than 8,700 gallons of gas – and it would
create nearly 11,000 tons of waste. 

It all comes down to this simple fact: We can't build our way out of the
global warming crisis. We have to conserve our way out. That means we
have to make better, wiser use of what we've already built. . .

Most recent efforts by the green community place heavy emphasis on new
technologies rather than on tried-and-true preservation practices that
focus on reusing existing buildings to reduce the environmental impacts
associated with demolition and new construction. The most popular
green-building rating system, the Leadership in Energy and Environmental
Design, or LEED program developed by the U. S. Green Building Council,
was designed principally for new construction – underscoring the fact
that words like "rehabilitation" and "reuse" haven't had much resonance
in the green-building lexicon.

This emphasis on new construction is completely wrong-headed. The
statistics I cited earlier tell us clearly that buildings are the
problem – but incredibly, we propose to solve the problem by
constructing more and more new buildings while ignoring the ones we
already have.

No matter how much green technology is employed in its design and
construction, any new building represents a new impact on the
environment. The bottom line is that the greenest building is one that
already exists.

It's often alleged that historic buildings are energy hogs – but in
fact, some older buildings are as energy-efficient as many
recently-built ones, including new green buildings. Data from the U.S.
Energy Information Agency suggests that buildings constructed before
1920 are actually more energy-efficient than buildings built at any time
afterwards – except for those built after 2000. Furthermore, in 1999,
the General Services Administration examined its buildings inventory and
found that utility costs for historic buildings were 27% less than for
more modern buildings.

It's not hard to figure out why. Many historic buildings have thick,
solid walls, resulting in greater thermal mass and reducing the amount
of energy needed for heating and cooling. Buildings designed before the
widespread use of electricity feature transoms, high ceilings, and large
windows for natural light and ventilation, as well as shaded porches and
other features to reduce solar gain. Architects and builders paid close
attention to siting and landscaping as tools for maximizing sun exposure
during the winter months and minimizing it during warmer months. . . 

I'm not suggesting that all historic buildings are perfect models of
efficient energy use – but, contrary to what many people believe, older
buildings can "go green." The marketplace now offers a wide range of
products that can help make older buildings even more energy-efficient
without compromising the historic character that makes them unique and
appealing. And there's a large and growing number of rehab/reuse
projects that offer good models of sustainable design and construction.

More recent buildings – especially those constructed between the 1950s
and 1980s – pose a greater challenge. Many of them were constructed at a
time when fossil fuels were plentiful and inexpensive, so there was
little regard for energy efficiency. In addition, they often include
experimental materials and assemblies that were not designed to last
beyond a generation.

Today, these buildings make up more than half of our nonresidential
building stock. Because of their sheer numbers, demolishing and
replacing them isn't a viable option. We must find ways to rehabilitate
these buildings and lighten their environmental footprint while still
protecting their architectural significance. . .

t makes no sense for us to recycle newsprint and bottles and aluminum
cans while we're throwing away entire buildings, or even entire
neighborhoods. This pattern of development is fiscally irresponsible,
environmentally disastrous and ultimately unsustainable.

http://www.nationaltrust.org/news/2007/20071213_scully.html

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