Retrofits Always "Greener?"
As a new study from the Preservation Green Lab [part of the National Trust for Historic Preservation] shows, the answer is “a resounding ‘usually.’”
Turns out, the question of building reuse is much more nuanced and interesting than can be answered with an blanket strategy – which is not at all surprising. Whether an existing building should be retrofitted or demolished is a question of use [both previous and planned], climate, construction type/materials, etc – and also a clear understanding of carbon footprinting: “Since it can take decades for a new building to “pay back” its embodied carbon through improvements in operational efficiency (see “A 2030 Challenge for Building Product Manufacturers,” EBN Feb. 2011), this study’s conclusions about carbon emissions should come as no surprise: based on climate-change considerations alone, almost every useable building in every region of the U.S. should remain standing—even if these buildings are not retrofitted to improve energy performance.
Carbon payback time for the buildings studied ranged from 10 to 80 years.” In any case, studies like this should have a big impact on how we think of using, and reusing, our existing urban fabric – both as designers, and as people with a vested interest in legitimate, effective responses to climate change. -Marilyn.