US Treasury headquarters believed to be oldest LEED-certified building
The third-oldest federal building in Washington, the US Treasury Department’s headquarters, was recently awarded LEED Gold certification after extensive renovations. It is believed to be the oldest building in the world to receive LEED certification.
Constructed over 33 years between 1836 and 1869, the building underwent recent improvements to save water and power. The work included measures to increase natural light, installation of advanced management of heating and cooling systems, and steps to increase recycling. The improvements are saving taxpayers $3.5 million in annual facility costs, the treasury department says.
(http://www.washingtonpost.com/local/at-142-years-old-us-treasury-building-wins-green-building-certification-after-improvements/2011/12/21/gIQABlrl9O_story.html)