Glass Towers Lag Behind 80 Year Old Buildings in Energy Ratings

In what some have called a shocking development, a new report from New York City calls into question the “greenness” of the venerable glass tower. As Mireya Navarro reports for the New York Times:

In courting tenants over the last six years, 7 World Trade Center has trumpeted its gold LEED rating, an emblem of sound environmental citizenship.

But when it comes to energy efficiency, the young 52-story tower is far from a top performer, according to data released under a city law that tracks energy use in New York buildings. It had a score of 74 — just below the minimum of 75 set for high-efficiency buildings by the federal Environmental Protection Agency’s Energy Star program.

On the other hand, two venerated show horses from the 1930s, the Chrysler Building and the Empire State Building, sailed to an 84 and an 80 as a result of extensive upgrades of their insulation and mechanical systems.

And the MetLife Building, a 1963 hulk looming over Grand Central Terminal? It scored 39. Still, solace is at hand for MetLife’s owners: the Seagram Building, Mies van der Rohe’s bronze-toned 1958 masterpiece on Park Avenue, posted a 3.

So cladding an entire building with the least energy efficient building system in common use makes for energy hogs? Shocking! Even with all of the advances in glazing technology (double glazing, triple glazing, various high performance coatings, thermally broken frame systems, even ventilated double walls), renovated 80+ year old buildings can outperform new LEED Gold glass towers. There seems to be a pervasive myth that glass towers are somehow green. While it is true that a glass tower can beat some energy benchmark and collect some LEED points in the process, it is also true that glass remains one of the least energy efficient cladding systems and glass towers that achieve LEED certification could be much more energy efficient if designed with a different cladding system.