DOE Study Shows Window Retrofit System Slashes Energy Use at Philadelphia Midrise
February 23, 2012

Built in 1972, 400 Market Street is a 200,000-square-foot, 12-story midrise in Philadelphia that was selected to be part of a $1.6 million Department of Energy (DOE)-funded project, last year. The project aimed to demonstrate the ability of low-E retrofit glazing systems to improve the energy efficiency of older commercial and residential buildings, and involved J.E. Berkowitz (JEB) LP of Pedricktown, N.J., Quanta Technologies Inc. of Malvern, Pa., and NAHB Research Center of Upper Marlboro, Md.

Using sophisticated energy modeling software provided by the DOE before the renovation, officials at JEB estimated that the retrofit would reduce annual energy costs at by $55,000. The first results since the project was completed show the building outperforming the projection.

"While our study has just started, preliminary observations are very encouraging," says Thomas Culp, manager of the DOE project and president of Birch Point Consulting LLC of La Crosse, Wis., in the release. "In November and early December, the east-facing offices showed about a 27 percent reduction in heating and cooling energy use, and the north-facing offices showed more than a 50 percent reduction. I will be very interested in seeing the continued results through the full winter."

The owners of 400 Market Street chose Renovate by Berkowitz (RbB), an on-site window retrofitting system developed by JEB, that converts existing single-pane windows into energy-saving, triple-glazed insulating glass units (IGUs), while preserving a building's exterior.

A lot of attention is given to new windows and buildings, while ignoring the vast amount of energy being wasted in older buildings with single glazing," Culp says in the release. "400 Market Street is the first of multiple case studies of the RbB system in commercial buildings to determine year-round energy savings and other benefits."

Officials at the NAHB Research Center is monitoring indoor conditions and energy consumption. While the utility usage of the entire building is being examined, the main technical analysis is from isolating and monitoring energy use in two pairs of unoccupied offices facing different directions-north and east. Within each pair, one room has been retrofitted with RbB while its twin will be left with no renovation until the end of year-long study.

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