Window Selection Methodologies and Optimiation in High-Performance Commercial Buildings

Recent research estimates that windows in commercial buildings are responsible for almost 1.5% of the total U.S. energy consumption (Apte and Arasteh, 2006). Therefore, selecting appropriate high-performance windows is important in terms of energy consumption and savings and also in terms of occupant comfort and productivity. Determining the optimum window design for a high-performance commercial building helps decision-makers (architects, designers, building owners, building operators) in the design and selection process of glazing products and attributes in a set of situations and conditions (orientation, window area, shading type, and glazing type).

This study focuses on the energy performance (energy and peak demand), carbon emissions, and to a lesser extent, the human factor issues (glare and thermal comfort) of a hypothetical 3-story, 48,000 square foot office building. The design parametrics considered are orientation, daylighting controls, window area, shading type, and glazing type. This study uses an existing simulated data set (8640 records for 6 U.S. cities) that was generated using generic set of commercial glazing products and this data set was analyzed in terms of annual energy performance and carbon emissions to determine the optimum window design in a heating-dominated and cooling-dominated climate.