Regarding the 2012 Report: “‘The Greenest Building is the one already standing’, Carl Elefante’s great line, has been the mantra of the green preservation movement, and I have used it a lot on TreeHugger. But while we knew it intuitively, we never had any real data. Until now, with the release of The Greenest building: Quantifying the Environmental Value of Building Reuse, released this morning. The report uses Life Cycle Analysis, (LCA) to compare the relative impacts of building reuse and renovation versus new construction.
“This study examines indicators within four environmental impact categories, including climate change, human health, ecosystem quality, and resource depletion. It tests six different building typologies, including a single-family home, multifamily building, commercial office, urban village mixed-use build- ing, elementary school, and warehouse conversion. The study evaluates these building types across four U.S. cities, each representing a different climate zone, i.e., Portland, Phoenix, Chicago, and Atlanta.
“The key findings show that the mantra is true, the greenest brick really is the one already in the wall, but with some caveats and qualifications.
“Building reuse almost always yields fewer environmental impacts than new construction when comparing buildings of similar size and functionality.
“The range of environmental savings from building reuse varies widely, based on building type, location, and assumed level of energy efficiency. Savings from reuse are between 4 and 46 percent over new construction when comparing buildings with the same energy performance level.
“Now I must confess I was a bit shocked and disappointed when I saw those numbers in the lefthand column, only 9% to 16% reductions in climate change savings by keeping the old instead of building new. I asked Patrice Frey of the Preservation Green Lab and she pointed out that this was actually a big number.
“In fact, replacing an average building with a new, more efficient building still takes as many as 80 years to overcome the impact of the construction. (Alter, 1/24/12)