Wall Street Journal

16 August 2010

Empire State Building Goes Green, One Window at a Time

Maya Pope-Chappell for The Wall Street Journal

A fifth floor space inside the Empire State Building has been transformed into a cramped window-making workshop.

By David Roth

How does a Depression-era skyscraper go green? For the Empire State Building, which is in the middle of $550 million renovation that includes about $100 million in energy-efficient upgrades, all 6,514 windows must be replaced. And that’s no easy task.

As The Journal’s Anton Troianovski reports, the greening of the iconic 79-year-old tower has become a platform for Anthony Malkin, the real-estate scion who runs the building, to criticize as insufficient popular programs for assessing the environmental sustainability of buildings. If the world follows the U.S. lead on energy use, he told the audience at a real-estate panel earlier this summer, “We’re all going to die and we’ll go to war along the way.”

For the Empire State Building’s windows, Malkin brought in Serious Materials to handle a pane-by-pane upgrade. The Silicon Valley-based building materials company is transforming the old, inefficient windows into “super-insulating” units, a sort of glass sandwich that combines the existing panes with a mixture of inert gases and film. The finished product is a window anywhere from 250% to 400% more efficient than the windows they replace, according to the company.

“Dirty little secret: double-pane windows aren’t all that efficient,” says Serious Materials CEO Kevin Surace.

The replacement windows, which use what Surace calls a “suspended film system,” break up the convection current between the inside and outside of a building. That means less heat sneaks in through the windows on hot days when the air-conditioning is running, and warm air from inside has a harder time leaking out when it’s cold outside.

The team of workers tasked with the window upgrade spend their days removing, cleaning and re-fabricating the building’s 12-year-old double-pane windows. The process, which began in March and is expected to run until October, is projected to reduce solar heat gain by more than half and save $400,000 each year in energy costs.

The window work is being done on site, in an office-turned-workshop on the Empire State Building’s fifth floor. Malkin estimates that keeping the process in-house saves $2,300 per window. The Serious Materials workspace buzzes between 7 a.m. and 2 a.m., processing 75 windows per day in a space roughly the size of a Manhattan apartment. The room is so snug that engineers for the project had to shrink some of their equipment to fit in the space.

Keeping the workshop on site ensures the windows are out of their frames for just about 20 hours before the upgraded window is ready. The process is designed to keep waste at a minimum: just 4% of the building’s existing windows are being discarded, and only the gasket surrounding the original windows winds up in the trash.

Workers remove the windows from office spaces at night and bring them downstairs to the workshop. Once there, the windows are removed from their frames and peeled apart like Oreo cookies before being cleaned. The first cleaning is manual, using razor blades and pumices, followed by a wash with a chemical solution and finally water.

The deconstructed windows are then fitted with new steel spacers, treated with a metallized film and baked flat in an oven at 205 degrees. The windows are then sealed with a mixture of Kyrpton and Argon gas. Finally, the upgraded windows are put back — with the help of careful but firm malleting — into their original aluminum frames.

The on-site re-use and refabrication of the Empire State Building’s windows is unprecedented on a project of this size. But Paul Rode, the project executive from Johnson Controls Inc. who is overseeing the retrofit, believes it could become a popular model in the industry. “I’m never waiting for product. If a problem ever comes up, we don’t have to call someplace that’s 500 miles away,” he says. “Logistically, that’s just what you want in the construction business.”