How Fenestration Can Significantly Affect Energy Use in Commercial Buildings

Fenestration can have a significant impact on the net annual energysconsumption of buildings. Proper design and effective management ofsfenestration can provide substantial energy savings. In order to maximizesenergy benefits and minimize costs, it is necessary to understandsbuilding energy performance in sufficient detail to assess componentsimpacts. This paper reports conclusions of an extensive series of computersanalyses of annual energy use and electrical peak demand in twosclimates as functions of fenestration parameters. Particular attentionsis paid to daylighting and its associated energy tradeoffs. The studysincludes the effects of climate, orientation, glazing area, U-value,sshading coefficient, visible transmittance, lighting power density, andslighting control strategy.

The extensive set of parametric analyses generated in this studyssuggest that for a simple office module, fenestration can provide annualsnet energy savings in all climates if daylighting is used. Control ofssolar gain is critical to realization of energy benefits from daylighting.sFenestration and daylighting design strategies that reduce netsannual energy consumption can also reduce peak electrical demand. Thesoptimum combination of fenestration variables is a function of climate,sorientation, and electric lighting power density.