In February 2012 the National Trust for Historic Preservation’s Preservation Green Lab released The Greenest Building: Quantifying the Environmental Value of Building Reuse. This report marks the first of its kind in the United States to compare the environmental consequences of reusing and retrofitting an existing building for energy efficiency versus building new. The findings make a compelling case that the preservation, retrofit, and reuse of a historic building is almost always a more environmentally sustainable option than new construction. This white paper is designed to help preservation professionals and advocates use the data contained within the report to advance their own efforts to save historic places. In it you will find:

• Definitions of common green building terms as well as an explanation of the building types and impact categories used in the report. 
• Concise explanation of the report’s scientific methodology (Life Cycle Assessment) and the study’s research objectives and steps.
• Breakdown of the report’s findings and what they mean for historic preservation.
• Guide to how to use the report to make the case for historic preservation.