Title 24 residential fenestration in California explained: §150.1 prescriptive limits, west-facing caps, high-rise multifamily rules, and window film options.

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.