“We shape our buildings; thereafter they shape us.”
Winston Churchill
There is a head-spinning number of tear-downs happening around my neighborhood and city. It makes me cringe when I see that big pile of bricks, wood, concrete, and shingles getting shoveled into a dump truck to be hauled off to the landfill. It just seems so wasteful. On the other hand, older structures are less energy-efficient than new ones. There have been so many recent innovations in building materials and techniques, which can make new homes more sustainable. So I have often wondered whether it is more climate-friendly to renovate or tear down.
New research from the University of Notre Dame offered some clarity on this question. ND happens to be my alma mater, so this admittedly made me extra curious. Architecture professor Ming Hu and her team created a tool to analyze buildings and quantitatively demonstrate the carbon trade-off between renovating and rebuilding. They studied more than a million buildings in Chicago, and found not one single example where tearing down and building new would result in lower carbon emissions.
Embodied carbon
So, why is this true, even if the new structure has all the latest “green” innovations? Well, obviously, buildings create emissions when we use them, primarily through heating, cooling, and electricity. But, existing structures also have what’s referred to as embodied carbon. This includes the sum of all emissions expended during the entire lifecycle of the structure: from creating, extracting, and transporting the materials, to the energy used to build and tear them down.
Renovate or tear down?
When taking embodied carbon into consideration, retrofitting an existing building always equals fewer emissions than tearing down. So, if you’re ever facing the decision, there may be lots of reasons to tear a home down, but one of them isn’t that it would be better for the climate. As Carl Elefante, former president of the American Institute of Architects, so concisely put it: “The greenest building is…one that is already built.”
Let’s do something about climate change. Learn about it. Talk about it. Help solve it.