Retrofits almost always more sustainable than new green construction

Despite all of the available technology and new green materials available today, retrofitting an existing building is almost always a more sustainable option than tearing an old building down and rebuilding it. The National Trust for Historic Preservation published a new study comparing the environmental impact of retrofitting an old building with tearing it down, trashing the debris, clearing the site, crafting new materials, and putting up a replacement from scratch.

Retrofit an existing building to make it 30% more efficient, the study found, and it will essentially always remain a better bet for the environment than a new building built tomorrow with the same efficiencies. Compare the new building’s life cycle to an average existing structure with no retrofitting, and it could still take up to 80 years for the new one to make up for the environmental impact of its initial construction.
(http://www.ecobuildingpulse.com/news/2012/01-january/2030-challenges-energy-reduction-target-within-reach.aspx)