In 2010 Alpen glass innovators executed an extraordinary window energy efficiency upgrade at the Empire State Building as part of a whole building efficiency improvement project that included 8 core improvement measures. Today, Johnson Controls reports:
World’s Most Famous Office Building Exceeds Energy Efficiency Savings for 3rd Consecutive Year; Annual Savings 16% Above Target
The Empire State Building has surpassed the energy savings guaranteed through its innovative energy-efficiency program for the third consecutive year.
Over the past three years, the program has generated a total of approximately $7.5 million in energy savings at the landmark building. The savings is the result of continued enhancement of the iconic building’s new systems and the addition of many new tenants occupying hundreds of thousands of square feet of office space retrofitted according to program guidelines.
Window improvements are continuously cited as one of the most dramatic contributors to these ongoing savings exceeding all expected results.
Knowing windows would be important, the design team wondered how to execute the improvement: complete removal of the relatively new, good condition, 1994 thermally broken aluminum frames was noted as an unnecessary waste and too costly. One day while watching maintenance staff clean the double-hung windows, Alpen Inc. founder and suspended film pioneer, Robert Clarke, saw an incredible opportunity to improve center-of-glass performance while re-using over 95% of the existing glass.
Starting in March, 2010, the Alpen and Serious Energy team built a suspended coated film fabrication line inside the Empire State Building. Over the course of 8 months, the team removed and replaced all 6,514 insulated glass units from the windows (rate of 150 per night), to add a low-e coated suspended film in the center of the units to create a triple pane, low-e coated window.
With Krypton gas fill, the new Alpen glass achieved center-of-glass U-value reductions of:
- North: -73% (from U-0.48 to new U-0.13)
- South/East/West: -59% (from U-0.48 to new U-0.20) plus -52% solar gain reduction
Contact Alpen HPP with questions about this project, or read the full reports from all three years of performance monitoring viewed at www.esbsustainability.com.