In the zeal to "go green," new construction that uses sexy, high-tech ways to reduce energy consumption gets the most attention, but historic preservation has been green all along. The most e nv i r o n m e n t a l l y responsible approach is to conserve, not to waste what's already built.
I applaud the U.S. Green Building Council's Leadership in Energy and Environmental Design process, and I hope to see preservation receive more favorable treatment in its rating system. LEED is geared for consumption: it gives points for recycling in a construction project but no points for keeping an entire historic building. It assigns no negative points for the loss of embodied energy, consuming energy in demolition, sending tons to the landfill or building on former farmland.
Restoring historic structures and revitalizing older neighborhoods reduces waste and limits the demand for new infrastructure and new materials. In renovating a historic structure, you preserve a limited resource and conserve embodied energy-the energy already spent to quarry the limestone, make the bricks, mill the lumber. And historic buildings are inevitably made of organic products, either renewable or long-lasting ones that are low on the energy-consuming scale-wood, brick, limestone, slate, plaster- rather than aluminum, vinyl and plastic.
Unlike much of contemporary construction, our forebears made places to last. And they built with efficiency and sustainability in mind, before they were buzzwords. Old buildings have high ceilings, transoms and operable windows placed for cross-ventilation and "daylighting" (the new term for using natural light from windows and skylights to reduce electricity demand). Pre-World War II buildings used porches, canvas awnings and shutters-operable ones-not for decoration but to screen a room during the heat of the day. They have plaster walls and ceilings, much more energy-conserving than drywall. Many have (or had) wood storm windows and screens that, with proper maintenance, would outlast a human lifetime. Our ancestors also strategically planted trees to screen and shade buildings.
But aren't old buildings energy hogs? Some are, but so are many newer buildings. Can historic buildings be made more energy-efficient? Of course. Attic, crawlspace and basement insulation make a big difference in energy consumption. A yearly check of caulking around windows, doors and the sill of a building is essential. (Most heat loss in a building is through the roof and the sill, not the windows or the walls.) Storm windows, interior or exterior, also make a difference.
I plead for retaining historic windows. Original windows are an essential feature of an old house or commercial building. Heavy advertising convinces owners they need vinyl replacement windows, but these often do not duplicate the size and shape of the original opening, and they're not paned in the same pattern or dimension. Sometimes they lamely try to mimic the original with thin, flat plastic strips embedded in the double-paned glass-a fake and pale imitation. In less than a generation, the replacement windows will need to be replaced, whereas old windows can be repaired and weather-stripped. You can reglaze existing panes, or retrofit the wood frames with laminated or insulated glass, and maintain the original appearance of the house.
The National Trust for Historic Preservation's sustainability initiative combines educating policy-makers, quantifying environmental impacts of demolition and new construction vs. preservation, and promoting ways to employ green technologies in rehabbing older structures.
In our 21st-century zeal to be green, we should remember the age-old adage, "waste not, want not." Preserving old buildings is all about not wasting: not wasting energy and labor, not wasting irreplaceable architecture, not wasting culture, and not wasting evidence of history and the lives of those who preceded us on this planet.
Davis is president of Historic Landmarks Foundation of Indiana.