Here's a tip for Manhattan building owners looking to build as energy-efficiently as possible: Build your structure 100 years ago.
New York City's recently implemented law mandating that buildings report energy use has revealed that the city's best performers are often not its newest additions. From the Times:
Older buildings tend to have higher Energy Star scores because they have thicker walls, fewer windows and less ventilation -- superior “thermal envelopes,” as a report on the early results puts it. They are also less suited to energy-gobbling activities like computer data crunching, the downfall of some youthful but middling performers. ...
Unlike cities that depend heavily on automobiles, New York racks up most of its carbon dioxide emissions -- nearly 80 percent -- in heating and cooling buildings. Tracking this energy use is deemed crucial to meeting the city goal of cutting overall emissions by about a third by 2030, to slash costs and fight climate change.
New York’s largest buildings -- just 2 percent of the roughly one million buildings in the city -- account for 45 percent of the energy expended by the entire building stock.
We took the data -- which is available online -- and mapped it by address. (We chose to use greenhouse gas emissions, since the metric used by the Times, its Energy Star rating, had far fewer data points. Clicking an address will reveal both its GHG emissions and efficiency rating.)