The greenest building… is the one that is already built.

Buildings represent enormous investments in energy, material, and financial resources and yet thousands of viable buildings are destroyed every year in the name of progress. The scale of such wastefulness is even more troubling as the world confronts climate change and the need for rapid reductions in greenhouse gas emissions.

Buildings cause global warming by consuming non-renewable energy for heating, cooling, lighting, and equipment (operational emissions) and also from building product manufacturing and construction (embodied emissions). For many buildings, embodied emissions are equivalent to two decades or more of operational emissions.

Retrofitting existing buildings to improve their performance can achieve energy efficiencies equivalent to new buildings, substantially reducing operational emissions while avoiding the immense embodied emissions from constructing a new building. Occupying, maintaining, renewing, and adapting existing buildings is the greenest approach and is especially crucial for meeting emissions reduction targets in the Paris Agreement on Climate Change.