Impact of Fenestration on Energy Use and Peak Loads in Daylighted Commercial Buildings

Effective utilization of daylight is one of several design strategies that promise to provide substantial energy savings for commercial buildings. Despite the revived interest in the field, there are very few occupied buildings for which performance data verify the magnitude and cause of real savings. In order to optimize costs it is first necessary to understand building performance in sufficient detail to assess the contradictory component impacts. This can be done most effectively using an hour-by-hour energy analysis model, in this case DOE-2.1B.

This paper reports conclusions of an extensive series of computer analyses in two climates to determine the energy use and demand impacts of fenestration in commercial buildings. Particular attention is paid to the tradeoffs involved in using fenestration to daylight perimeter zones. The study includes the effects of climate, orientation, window area, U-value, shading coefficient, visible transmittance, lighting power density, and lighting control strategy.