Statistics on the amount and distribution of windows on office buildings was not provided in the 2003 CBECS data. Appendix G of Standard 90.1-2004 required that the vertical fenestration areas modeled in the baseline equal the vertical fenestration area of the proposed design or 40% of the gross above-grade wall area, whichever was smaller. For the baseline and proposed model, the amount and distribution of windows was taken off of the existing architectural drawings of the building. The fenestration area equaled 7.8% of the gross above –grade wall
