Workers are removing every double-hung, double-pane window in the Empire State Building to make them more energy efficient. Workers add a layer of insulating film between the panes, cook the glass, add some inert gas and slot the windows back into their sashes so they can be put back on the building. Working by night, the team aims to change all 26,056 pieces of glass in what conservationists call "the most recognizable building energy retrofit in the world."

Full Story:
USA Today

Related Summaries