The DOE-2 building energy analysis computer program has been used to study the life-cycle cost and annual energy use for a wide range of glazing and sun-control options in a 25-story office building with 50% glazing. Four climates in the U.S. have been analyzed: Miami, Los Angeles, Washington, D.C., and Chicago. The impact of daylighting in the perimeter zones for the various sun-control options has also been investigated. Double glazing was found t o have little effect on energy use in Miami and Los Angeles, but reduced energy use 11 - 23% in Washington, D.C., and 16 - 32% in Chicago. Daylighting reduced energy use 10 ? 22% and had a simple payback period of 3.7 - 8.9 years depending on climate and type of fenestration. Of the alternatives considered, the lowest life-cycle cost and energy use were obtained with daylighting coupled with clear glazing and exterior sun-control blinds.