Historic Buildings and Being Green
The greenest building is the one that is already built. The U.S. General Services Administration, owner/manager of non-Military Federal Buildings, conducted a study and found that utility costs for historic Federal buildings were actually 27% less that the utility costs for modern buildings. Another study confirmed that buildings constructed prior to 1920 were found to be, on average, more energy-efficient than any building constructed between 1920 and 2000. It has only been in the new millennium that the emphasis on energy efficiency and green buildings has gotten us back to where we were 100 years ago.
Embodied Energy: Sustainable Stewardship
Richard Moe, President of the National Trust for Historic Preservation, describes embodied energy as follows:
“Buildings are vast repositories of energy. It takes energy to manufacture or extract building materials, more energy to transport them to a construction site, still more energy to assemble them into a building. All of that energy is embodied in the finished structure – and if the structure is demolished and landfilled, the energy locked up in it is totally wasted. What’s more, the process of demolition itself uses more energy – and, of course, the construction of a new building in its place uses more yet.”
The Historic 1918 Kasson School is comprised of approximately 30,000 square feet. The school has approximately 48 Billion BTUs of energy embodied within its construction materials. That is the equivalent of 384,000 gallons of gasoline. If you tear the building down, all of that embodied energy is wasted. Demolishing the school would create approximately 2,400 tons of waste headed to a landfill. After the building is gone, constructing a new building it its place requires more energy usage and it also uses more natural resources and releases new pollutants and greenhouse gases into our environment. It is estimated that constructing a new 30,000-square-foot building to replace the school releases about the same amount of carbon into the atmosphere as driving a car 1.7 million miles.
Richard sums up embodied energy as:
“You might think that all the energy used in demolishing an older building and replacing it is offset by the increased energy efficiency of the new building – but that’s simply not true. Recent research indicates that even if 40% of the materials are recycled, it takes approximately 65 years for a green, energy-efficient new office building to recover the energy lost in demolishing an existing building. And let’s face it: Most new buildings aren’t designed to last anywhere near 65 years.”
“A report from the Brookings Institution projects that by 2030 we will have demolished and replaced nearly 1/3 of all existing buildings, largely because the vast majority of them weren’t designed and built to last any longer. How much energy will it take to demolish and replace those buildings? Enough to power the entire state of California for 10 years.”