California Title 24 §140.3 explained for 2026: prescriptive U-factor and SHGC limits, the 40% window-to-wall ratio trap, §141.0 alterations, and how XPEL Vision commercial window film gets Los Angeles nonresidential buildings compliant.

California Title 24 §110.6 mandatory fenestration measures explained in plain language: the 0.3 cfm air infiltration limit, NFRC U-factor, SHGC and VT ratings, the 110.6-A and 110.6-B default tables, and how NFRC-certified window film complies. From Rapid Window Tinting, Los Angeles.

California is divided into 16 climate zones by the California Energy Commission. Title 24 fenestration requirements — SHGC and U-factor thresholds for window film — vary dramatically by zone, and a single county can span multiple zones. This guide walks through all 16 with cities, character, and the right film recommendation tier per zone.

California's 2025 Energy Code (Title 24 Part 6) took effect January 1, 2026, tightening envelope and fenestration criteria. Window film is an explicitly recognized retrofit measure that satisfies §110.6 mandatory measures, §140.3 prescriptive (nonresidential), and §150.1 prescriptive (residential) — often the lowest-cost compliance path for existing California buildings.