In Climate Zones 1 through 6, not more than 40 percent of the gross above-grade wall area shall be permitted to be vertical fenestration, provided all of the following requirements are met:
- In buildings not greater than two stories above grade, not less than 50 percent of the net floor area is within a daylight zone.
- In buildings three or more stories above grade, not less than 25 percent of the net floor area is within a daylight zone.
- Daylight responsive controls complying with Section C405.2.3.1 are installed in daylight zones.
- Visible transmittance (VT) of vertical fenestration is not less than 1.1 times solar heat gain coefficient (SHGC).
Exception: Fenestration that is outside the scope of NFRC 200 is not required to comply with Item 4.