Greening the Skyline: Small Fixes Save Big Money

The world's tallest buildings look modern but have old-school energy bills. Enter the new age of eco-upgrades for skyscrapers

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The Empire State Building slashed its utility bills by $4.4 million a year

One of the most ambitious efforts to transform city skylines around the globe is nearly invisible. That's because the changes, aimed at drastically reducing energy consumption and carbon emissions in tall buildings, are happening in places most people never venture — in subterranean boiler rooms, behind radiators, under desks and inside the massive walls of office towers built decades ago.

Skyscrapers look modern, but they are among the worst culprits in urban areas when it comes to energy consumption and carbon emission, with outdated heating, cooling and lighting systems. And there are a lot of them — some 3 million in the U.S. alone. "No matter what we do on the new-construction side, it is a fraction of what needs to be done with existing tall buildings," notes Rick Fedrizzi, CEO of the U.S. Green Building Council, which since 2002 has certified more than 1,000 energy-saving retrofits of existing buildings around the globe. An additional 5,234 retrofits are in the works. The work itself isn't cutting edge — it's about doing the basics better — but the savings add up: some 200 million metric tons of carbon would no longer be emitted each year.

One of the biggest success stories to date is the Empire State Building, which announced last fall that its new $13 million retrofit would pay for itself within three years, thanks to a 38% reduction in annual energy consumption. The total costs were partially offset by a $2 million grant from New York State. But Tony Malkin, owner of the Art Deco building completed in 1931, also managed to save money with novel ideas like refurbishing the glass in the building's windows instead of replacing it. Instead of paying $2,500 each to replace the 6,514 windows, Malkin spent $700 each to clean and insulate them. The contractors actually set up a window-refurbishing factory on the building's fifth floor in order to get the job done in less than six months last year. "The industry said it couldn't be done," says Kevin Surace, CEO of Serious Materials. Adds Malkin: "We did everything based on cost-effectiveness."

Most of the upgrades were downright ordinary. Workers recaulked the gaps between the limestone slabs on the building's facade to prevent heat loss, sprayed foam insulation in holes between the radiator pipes and walls and installed variable-frequency drives in the heating and cooling systems for precise temperature control. "I can't tell you how many people say, 'Why not install solar cells or put a little windmill on the roof?' Because it doesn't make business sense. It makes much more sense to lower energy use," says Paul Rode, the project manager at Johnson Controls who oversaw the Empire State Building retrofit.

Another myth is that it's harder to get energy savings out of old buildings. In some ways, they're easier to green, as they tend to be made out of better insulating materials, like masonry, instead of glass and metal. For newer edifices, architects have resorted to more novel approaches to prevent heat loss, like creating a second facade that envelops the original. The 32-story glass-and-steel Celebrezze Federal Building in Cleveland, built in 1967, is getting a second skin made of glass and aluminum, which will be paid for in part with funds from President Obama's stimulus program. Designed by architect Charles Young of Interactive Design Eight, the new facade will stand 2.5 ft. (75 cm) outside the old exterior. Airflow between the old and new facade will insulate the building, yielding an estimated energy savings of $650,000 per year.

Other high-profile retrofits are in the works. George Comfort & Sons, which owns the 50-story Worldwide Plaza in midtown Manhattan, hired Johnson Controls' Rode to manage its $15 million retrofit last year after touring the Empire State Building. And the city of Melbourne has launched an ambitious project aimed at reducing the energy consumption of about 1,200 office buildings 38% by 2020. "This is not some feel-good environmental initiative. It is a hardheaded economic business decision," says Robert Doyle, lord mayor of Melbourne. And not a tough one, given that the work will pay for itself in 10 years.