Historic buildings are one of the city’s most valuable cultural, economic and environmental investments. Conservation, reuse and renewal of these built resources are a critical part of the District of Columbia’s efforts to achieve a sustainable urban environment. The preservation and sustainability benefits that result from the adaptation and reuse of historic structures include: reductions in energy consumption and operating costs, preservation of the embodied energy of existing materials, elimination of waste associated with demolition, reinvestment in existing communities and infrastructure, and reductions in greenhouse gas emissions associated with new construction. Our city’s historic buildings are one of our most important renewable resources.
The Historic Preservation Office (HPO) serves as a resource for property owners seeking to improve their buildings in a manner that is sensitive to both sustainability and historic preservation concerns. The following information has been developed by the HPO and Historic Preservation Review Board (HPRB) to help property owners understand the opportunities and challenges in these efforts.
How are historic buildings and districts sustainable?
Historic districts are viable, environmentally-friendly communities. Most are pedestrian oriented neighborhoods with proximity to public transportation, an abundance of green space and a building density that efficiently uses land and resources. Historic structures are inherently “green.” Many older buildings were constructed with locally available materials and using energy efficient design and construction techniques. The traditional design of older buildings often includes such features as passive heating and cooling, and siting and building orientation sensitive to environmental and topographical factors.
Through the preservation of existing materials of historic structures, the “embodied energy” – that energy which was used to construct them – is conserved. By maintaining existing materials and adapting them with low impact energy technologies, historic structures and neighborhoods can stand as models of environmental stewardship through their dramatic reduction of energy use, material resources, and waste associated with new construction.
How is sustainability evaluated in historic preservation?
The fundamental measures of sustainable preservation consider the cultural, environmental and economic impact of a building throughout its lifespan. Whether a project’s goal is energy conservation or use of a renewable energy source, owners of historic resources can benefit from both the building traditions of the past and new technologies. When making sustainability improvements, the visual compatibility with the historic resource must also be considered.
Issues that may inform an owner’s decisions include:
• The lifecycle expectancy, durability and toxicity of new materials and building systems.
• The maintenance capability of a building’s owner and the lifecycle costs of material choices.
• The embodied energy that is conserved when retaining existing materials, and the amount of new energy required to produce, deliver and construct a building.
• The waste associated with replacing existing materials, including its disposal in landfills, and the use of energy to deliver and dispose of materials.
In recent years, participants in the green building movement have developed and used rating systems to evaluate the overall environmental performance of new and renovated structures. National organizations such as the US Green Building Council, the American Institute of Architects (AIA), National Park Service, National Trust for Historic Preservation, and others have been working together to better define the role of historic preservation in environmental sustainability.
Sources for more information on Preservation and Sustainability
A variety of web sites and publications provide additional information on the topic of Preservation and Sustainability including subsections for Energy Conservation, Green Building Guides, Window Repair and Energy Efficiency of Old Windows, Geothermal Energy, and Government Resources.