Energy, Green Building, and Sustainability: Title 24 Parts 6 and 11 and CALGreen
Two parts, two purposes
Title 24 Part 6 is the Building Energy Efficiency Standards. Part 11 is CALGreen. Part 6 regulates envelope, fenestration, lighting, HVAC, water heating, and renewable energy through prescriptive and performance paths. Part 11 regulates site sustainability, water efficiency, materials, indoor environmental quality, and construction waste.
Part 6 essentials
California has 16 climate zones, and compliance is climate-zone-specific through either a prescriptive package or performance modeling. Items that recur on exams: fenestration U-factor and SHGC, roof and wall insulation, cool roofs, lighting power density and controls, economizers, duct sealing, and commissioning. Recent editions require photovoltaic systems on new residential construction and extend solar and storage requirements toward nonresidential occupancies and multifamily buildings. HERS raters verify field features independently of the installing contractor.
CALGreen essentials
Mandatory measures apply statewide: construction waste diversion (at least 65 percent), indoor water use reduction, recycled-content materials, pollutant source control, and electric-vehicle-capable parking. Tier 1 and Tier 2 are voluntary reach levels a local agency may adopt as ordinance. Local ordinances exceeding Part 6 or Part 11 generally require Building Standards Commission approval as reach codes.
Traps
Swapping Part 6 and Part 11; treating Tier 1 as mandatory; assuming Title 20 appliance standards are part of Part 6; forgetting a local jurisdiction cannot simply invent stricter energy rules without state approval; confusing the commissioning agent's role with the HERS rater's.
Rule of thumb
If the measure governs energy used by building systems in operation, it is Part 6. If it governs site, water, waste, or materials, it is Part 11.