Preservation Is Better

by Don Friedman on May 12, 2017


A new study compares the environmental impact of replacing the buildings of the United Nations complex with retrofitting them. (A recently-completed project retrofitted them.) The short version: the higher efficiencies possible with mechanical systems in a new building would take at least 35 years (and maybe a lot longer) to overcome the environmental impact of the constriction of replacement buildings.

That may make it sound like there’s not a big environmental difference between reuse and new building, but not if we pay attention to time’s arrow. At some point, the new mechanical systems will be getting old, and some of the recent renovations will have outlived their usefulness, and the same question will come around again. Replacing buildings again and again is not economically sound and if the environmental costs of the new building outweigh potential savings for decades, then why wouldn’t we save the old?

People have an image of old buildings as being energy wasteful, as requiring more heating, air-conditioning, and lighting than their modern counterparts. That’s only true if we think of the old buildings as static and unchanging; if we assume that they will receive the same care and upgrades as modern buildings, they can perform just as or nearly as well.

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