International Construction Specialty Conference of the Canadian Society for Civil Engineering (ICSC) (5th : 2015)

Energy Star windows' performance and orientation Jalili, Maral; Clevenger, Caroline M.; Ozbek, Mehmet E.; Abdallah, Moatassem A.


In 2012 and 2013, ten building product categories were eligible for United States ENERGY STAR Federal Tax Credits. High performance windows that meet certain energy efficiency criteria are one of the qualifying products. The ENERGY STAR Tax Credit program sets U-factor and Solar Heat Gain Coefficient (SHGC) standards for these windows according to four climate zones. Research demonstrates that buildings with well-designed and constructed fenestration systems can lower requirements for heating, cooling and lighting during operation. However, previous research and energy modeling also demonstrates that, in addition to energy efficiency characteristics, orientation impacts the energy performance of windows. The ENERGY STAR tax program makes no distinction regarding window orientation or placement when evaluating tax credit eligibility. This research studies the potential impact of orientation on performance for qualifying ENERGY STAR window products. Using TRNSYS energy modeling comparisons, findings suggest that the performance of qualifying windows may vary up to 14 percent for different orientations depending on climate zone.

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