The area-weighted average maximum
fenestration U-factor permitted using tradeoffs from Section N1102.1.4 or N1105 shall be 0.48 in Zones 4 and 5 and 0.40
in Zones 6 through 8 for vertical fenestration, and 0.75 in
Zones 4 through 8 for skylights. The area-weighted average
maximum fenestration SHGC permitted using tradeoffs from
Section N1105 in Zones 1 through 3 shall be 0.50.