The Whole-Building Approach for the World’s Tallest

Monday, June 7, 2010

by Caroline Fluhrer & Rebecca Cole, RMI SOLUTIONS JOURNAL, Spring 2010

image How will we pay for it?

What retrofit projects should be implemented?

Who should do the work?

These are the key questions most building owners ask when embarking on a retrofit project. Yet many overlook what may make or break its success: timing.

In most cases, building owners consider a large capital investment generally for reliability, comfort or functionality—not to save energy. In doing so, they are overlooking the prime time to do an energy efficiency retrofit.

Energy efficiency measures are almost universally less cost-effective when done as stand-alone projects. However, when the principles of “integrated design” and “piggybacking” are applied to major capital investments in a building, energy efficiency measures can become highly profitable.

Integrated Design and the Empire State Building

A year after RMI and our partners completed an award-winning retrofit design of the Empire State Building, the $550 million capital upgrade program is now underway.

Overall, the complete energy efficiency program will generate $4.4 million in annual energy cost savings, and cut the building’s energy use by nearly 40 percent, all with an incremental payback of just over three years.

A major portion of the project is to retrofit every one of the building’s approximately 6,500 double-hung windows in order to quadruple their energy performance. Only 10 years old, the windows will be removed, converted into “super insulating glass units” in a special on-site assembly area on a vacant floor of the building, and re-hung.

This project will generate $410,000 a year in energy savings at a total capital cost of $4.5 million and an incremental capital cost of $4 million (since $500,000 was already budgeted for window sealing and isolated replacements). This stand-alone project has a simple payback of just less than 10 years.

However, to characterize the economics of this particular window retrofit project as having a “9.8-year payback” is overly conservative.

Because the window retrofit roughly halves solar heat gain, it reduces the building’s peak cooling load by 440 tons. The team was thus able to recommend the renovation and reduction of the existing chiller plant, at a capital cost of $5.1 million, rather than replacing and expanding it for $22.4 million. [Read rest of story]

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