The National Trust for Historic Preservation calculates that a newly built green building will save energy equal to the amount lost in demolition and reconstruction—in just 65 short years.
Constructing a 50,000-square-foot office building uses as much energy as a car driven for 14.6 million miles, according to NTHP. That doesn’t even account for landfill issues—about 25 percent of a city’s waste stream is construction debris.
If we continue the historical trend of knocking down one-third of our commercial space every quarter-century or so, that’s another 80 billion square feet of waste off to the landfill, and enough energy to power all of California for about 10 years—not to mention the associated greenhouse
Can we afford to hang onto inefficient vintage buildings? NTHP cites a U.S. Energy Information Agency report that found buildings constructed before 1920 are more energy-efficient than those built in later decades, while the GSA in 1999 found that utility costs for historic buildings were 27 percent lower than more recently construction buildings.
Of course, one reason is that older buildings lacked the electrical loads needed for computers and other office equipment. Vintage buildings are not space-efficient either, so the same numbers of workers need much more space in an old building than in a new one. If a study was done based on electrical usage per occupant rather than per square foot, historic buildings would not fare so well.
Nevertheless, if we’re going to get serious about reducing carbon emissions, we have to consider demolition and construction as well as operations. That’s a powerful argument for seeking every opportunity to retrofit and rehab rather than to raze and rebuild.