We are so accustomed to the idea that one should buy a new refrigerator or a new car in order to achieve improved energy efficiency that many of us probably think that the same applies to buildings. Not so, according to a report published earlier this year by the National Trust for Historic Preservation in the US. The Trust’s Preservation Green Lab, in partnership with several other organizations with expertise in green building and lifecycle analysis, came to the conclusion that the reuse of existing buildings almost always offers environmental savings over demolition and new construction.

The report claims that it can take between 10 and 80 years for a new, energy-efficient building to overcome, through more efficient operations, the negative climate change impacts that were created during the construction process. However, care must be taken in the selection of construction materials in order to minimize environmental impacts; the benefits of reuse can be reduced or negated based on the type and quantity of materials selected for a reuse project.

The report presents quite detailed findings supporting its conclusions and offering suggestions on environmental impacts by lifecycle stage so that, whether one is building new or renovating an existing building, one can see some of the steps in which more environmental sound choices can lead to a greener building.

Given that the report so clearly provides support to the Trust’s mandate it may take a few more such reports before the advice that greener buildings are restored existing buildings is widely accepted. However, the report is highly recommended to those interested in saving older buildings or in achieving the greenest possible building. It is available at http://blog.preservationnation.org/2012/01/24/preservation-green-lab-releases-new-report-on-the-environmental-value-of-building-reuse/