Sky Garden, Porches Dress Up Energy-Stingy PNC Tower

PNC Financial Group HQ
An architectural rendering by the architecture firm Gensler of the headquarters of the PNC Financial Group headquarters in Pittsburgh, an innovator in green design. The sloping roof, heated by the sun, acts like a chimney, drawing fresh air through the building's double-wall construction. Source: PNC Bank/Gensler via Bloomberg

A tower under construction in Pittsburgh aspires to be the greenest in the world. I’ve heard that one before, and I usually don’t buy it.

Yet the design of the 33-story PNC Financial Group headquarters impresses because amenities come with energy-conservation tactics that even the most ecologically oriented companies in the U.S. have largely shunned.

Sliding wooden doors open onto a breezy porch high above the city. Colleagues can gather to work casually in a sky-garden atrium offering panoramic views.

Hao Ko, a senior associate and design director at architecture firm Gensler, has fashioned what is on the outside a rather ordinary-looking glass box.

Working with Denzil Gallagher, principal at engineering firm Buro Happold, Ko wrapped the building in two walls. The three-foot space between them insulates in winter and rejects solar heat in summer, aided by automatic shades.

Windows can be used to ventilate the entire building naturally. Staffers also can adjust the temperature with the sliding wooden doors.

Why does PNC bother? Many experts think energy is abundant and a lot of people think global warming is a hoax. But Gary Saulson, the bank’s executive vice president and director of corporate real estate for the PNC Financial Services Group Inc., has championed energy and resource conservation at PNC since 1998.

‘Right Thing’

PNC has been building green “not because of any mandate but because it seemed the right thing to do,” Saulson said in an interview. “It makes sense economically and it boosts pride in our company.”

The bank, which has 118 LEED-rated buildings, says it has reduced its energy budget 25 percent since 2009.

I spoke with Saulson about the way the bank uses architecture in the pursuit of lower costs and higher productivity.

A wood window wall in a highrise? “It can be sourced locally,” Saulson said, and is an excellent insulator that also makes the workplace look more informal.

“We’ve angled the building and configured the interior so that 91 percent of it can be lit by natural light” alone, he said. A “solar chimney” on the roof heats air, causing it to rise, pull fresh air through the building and reduce the need for fans.

‘Natural Light’

Aside from the substantial savings, “people like natural ventilation, natural light and views,” Saulson said. “They like being able to control how warm or cool their environment is.”

The building will wrap meeting spaces around multistory west-facing atriums stacked on top of each other. Switchbacking stairs descend to sky gardens.

“You need a place for quiet work, to make private phone calls. But you also need spaces for collaboration,” Saulson said. “We want employees to be able to work in the environment where they can be most productive, not tied to their desks.”

The $400 million tower, scheduled for 2015 completion, won’t ostentatiously display windmills or photovoltaic panel arrays. Neither system delivered enough power for the cost. It will consume half the energy of a comparable structure by using about 30 efficiency tactics.

Higher Performance

Politicians argue over the usefulness of renewables. PNC shows that conservation delivers much higher performance at much lower cost.

Though no government programs subsidized PNC’s effort, strategically targeted incentives could rapidly widen the appeal of the building’s many innovations -- creating a diverse array of jobs.

Dramatic energy savings are easier to do in new projects, so I asked Saulson which tactics could be applied to other buildings in the company’s 30-million-square-foot portfolio.

“We can’t rebuild our footprint, but we can take what we learn from the tower and bring it into those buildings,” he said.

The bank is planning a branch in Fort Lauderdale, Florida, that will produce all its energy by solar on site.

(James S. Russell writes on architecture for Muse, the arts and culture section of Bloomberg News. He is the author of “The Agile City.” Any opinions expressed are his own.)

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