Retrofit of Single Pane Windows Cuts Energy Use 53%

by | Apr 2, 2013

The Renovate by Berkowitz (RbB) window retrofitting system has enabled 400 Market Street, a 12-story building in Philadelphia, to reduce energy consumption in some perimeter offices by 53 percent, according to results from a year-long energy study.

Built in 1972, the 200,000-sq-ft building was retrofitted with the RbB system in late 2011, converting its original single-pane windows into triple-pane insulating glass units.

As part of a $1.6 million US Department of Energy-funded study conducted by the NAHB Research Center and Quanta Technologies, the building was selected as a real-world case study to demonstrate the ability of low-e retrofit glazing systems to improve the energy efficiency of older commercial buildings. The study examined four unoccupied perimeter offices in the building, two facing east and two facing north. One office in each pair was retrofitted with RbB, while the other was left untouched.

According to project manager Thomas Culp, of Birch Point Consulting, the renovated north-facing office saw a 33 percent reduction in total energy usage and the east-facing office saw a 53 percent reduction.

The DOE estimates that inefficient windows account for as much as 25 percent of a typical building’s heating load in cold climates and 50 percent of the cooling load in warm climates.

RbB is suited for all weather conditions. Results will vary from location to location.

Because the RbB system is a pre-assembled insulating glass unit that is installed to the existing interior window surface, it is faster and less disruptive to install than a traditional rip-out-and-replace project. Tenants of the Philadelphia building were able to stay in their offices, saving the time and costs associated with temporarily relocating them. And, according to Kaiserman Company, the owner of the building, the maintenance staff has noted reduced cycling times on the boilers along with the ability to lower hot water set points.

The Kevon Office Center in Pennsauken, NJ, was also retrofitted with RbB.

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