Cornell Tech is building an applied sciences campus on Roosevelt Island in New York City. Work has begun and, when completed, it will feature environmentally friendly classrooms and lots of green space. But its most noteworthy feature will be a 250 foot tall residential high rise dormitory building so energy efficient it could change the way buildings are constructed in New York City, if not the rest of the country. Designed to house 520 people when it's completed in 2017, the dormitory will be the tallest passive house building in the world. 

Meeting passive house (or Passivhaus) standards costs about 5% more money than normal construction. But the dormitory will use as much as 70% less energy for heating and cooling during its lifetime, repaying that initial cost penalty many times over. It will save 882 tons of CO₂ each year compared to a normal building.

In order to meet the standards, "You need to have every crack sealed," according to Blake Middleton, a partner at Handel Architects, which designed the building. Essentially, the Cornell building has to be completely airtight to pass muster. "It requires a much higher degree of care than is traditionally found in sealing up the envelope of a building for more conventional construction," says Middleton.

Normally, a building like this would feature floor to ceiling windows for sweeping views of the city, but meeting Passive House standards would require essentially a building within a building. That would increase construction costs dramatically. Cornell opted for slightly smaller windows instead.

"There will be well-sized windows that take advantage of views, but they're not as big as they might be if they were catering to the [condo] market," says Arianna Sacks Rosenberg, a senior project manager at Hudson, the developer behind the $115,000,000 high rise.

The airtight design, combined with a heat recovery ventilator system that brings in fresh air from outside, means the building doesn't need much in the way of a heating and cooling system. The ventilator system chosen was not approved by the New York City building code, so the developers had to get special permission to install it.

In the US, Passive House standards are usually reserved for single family homes, but the Cornell dormitory may lead the way toward applying them to larger buildings as well. Two decades ago, LEED standards that are considered standard procedure today required many changes to existing building codes.

"In a way, it's like we're beta testing a new model of a car that everybody already knows pretty well, but there are certain tweaks going on, and components in that car that have to be machined better, to fit more exactly," says Middleton.

All those tweaks are helping to pave the way to a more energy efficient urban future.

Editor's note: Although the passivhaus principle represents the highest standard in energy efficient building, the management of this particular development and the site construction approach have found vocal critics. They make ethical points and criticize the demolition of  trees on the site. Read about these here.

Source: Building Insider  Image Credit: Handel Architects

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