San Francisco is in California Climate Zone 3, and its Title 24 Part 6 compliance profile is distinctly different from Los Angeles's Climate Zone 8/9 pattern. SF's mild, heating-dominated climate means Title 24 prescriptive-path requirements emphasize envelope insulation, air-sealing, and low-U-factor windows far more than cooling efficiency. But SF adds a San Francisco-only Existing Buildings Energy Performance Ordinance (SF Environment Code Chapter 20) on top of state Title 24, creating a two-layer compliance regime that LA doesn't have. San Francisco DBI (Department of Building Inspection) at https://sfdbi.org/ enforces both layers in a single permit workflow.
How SF DBI implements Title 24 and the Energy Ordinance
DBI's permit workflow through DBI Online requires Title 24 compliance documentation (CF-1R, CF-2R, CF-3R forms) on any permit that touches envelope, HVAC, water heating, lighting, or electrical service capacity. Separately, SF's Existing Buildings Energy Performance Ordinance requires non-residential buildings over 10,000 square feet to file annual energy benchmarking and undergo audits every five years — a requirement that doesn't exist statewide. For residential buildings, the Energy Ordinance doesn't create new CF forms, but it does interact with Title 24 when residential buildings trigger substantial alterations that move them across the threshold.
SF DBI's plan-check team absorbed Title 24 review into generalist plan examiners rather than maintaining a dedicated Green Building division (LADBS's approach). In practice, this means SF homeowners should bring a complete, well-documented CF-1R to plan-check intake — unlike LA, where consultation with the Green Building Division is possible before formal submittal. DBI publishes current plan-check turnaround at https://sfdbi.org/permit-turnaround-times, and Title 24 review adds typically 1-2 weeks to the baseline plan-check timeline.
The Climate Zone 3 prescriptive path
San Francisco Title 24 Climate Zone 3 prescriptive-path requirements emphasize:
- High wall R-values (R-20 or greater for 2x6 exterior walls) driven by heating-dominated climate demand
- Air-sealing with blower-door verification per the Residential Compliance Manual
- Low-U-factor, low-SHGC windows (though SF's mild climate relaxes SHGC slightly compared to cooling-dominated zones)
- Efficient heating systems — heat pumps favored by the 2025 update
- Water heater requirements favoring heat pump water heaters on the prescriptive path
Gas heating system replacements in SF trigger the same 2025 prescriptive-vs-performance decision as LA, but because SF's heating load is lower and cooling negligible, the performance-path energy model is often easier to pass. SF DBI plan examiners are slightly more accommodating to performance-path submittals on older wood-frame SF housing stock where prescriptive insulation requirements would require tear-out of historic plaster walls.
Hyperlocal enforcement realities in San Francisco
SF DBI inspectors flag these SF-specific Title 24 patterns:
- Older wood-frame wall insulation retrofits. SF's pre-1940 Edwardian and Victorian housing stock often has no wall insulation. Adding insulation triggers Title 24 wall R-value compliance, but the structural wall assemblies can't always accept R-20. DBI plan examiners accept performance-path alternatives that bring overall building envelope up to code even when the walls can't.
- Interior-only remodels that trigger exterior Title 24 compliance. Under the 2025 Code, substantial alterations affecting more than 50% of a wall or ceiling area can trigger Title 24 compliance on the entire wall or ceiling. Homeowners doing "just interior" remodels in historic SF buildings frequently discover this at plan-check.
- Ductwork in conditioned crawlspaces. SF's coastal climate creates complex crawlspace moisture patterns. Ducts in crawlspaces must be sealed and insulated per Title 24, and DBI inspectors regularly fail ductwork that's been field-retrofitted without proper mastic sealing.
- Window SHGC interpretation for fog-belt neighborhoods. The outer Sunset, outer Richmond, and Ocean Beach neighborhoods have such low solar gain that SHGC requirements feel over-specified. DBI's plan examiners follow the prescriptive table strictly, though, and don't accept "fog-belt" as a performance-path justification.
- Soft-Story Retrofit projects and Title 24 interaction. When SF soft-story retrofits touch the ground-floor envelope, Title 24 envelope compliance is triggered at the new garage-to-conditioned conversion. Many soft-story projects underestimate Title 24 scope.
What San Francisco homeowners should verify
Before signing an SF construction contract, verify the contractor has Title 24 experience specifically in Climate Zone 3. Contractors who normally work outside the Bay Area may default to Climate Zone 4 or Climate Zone 8 values. Ask for two prior SF projects that closed with Title 24 final and verify those permits in DBI's Property Information Map.
Second, coordinate the HERS rater early. SF has fewer HERS raters per capita than LA, and CalCERTS rater availability can add 2-4 weeks of scheduling slack if not booked at rough-in.
Third, understand your Climate Zone 3 envelope requirements before finalizing the design. Thin-wall historic construction may push you toward performance-path compliance — factor that into the design budget.
FAQ
How does SF Title 24 differ from LA Title 24?
The statute is identical but Climate Zone 3 (SF) prescriptive requirements emphasize heating envelope where Climate Zone 8/9 (LA) emphasizes cooling. SF also layers Chapter 20 Energy Performance Ordinance on non-residential buildings over 10,000 sf, which LA doesn't have.
Does SF's Soft-Story Retrofit Ordinance trigger Title 24?
Partially. If the retrofit converts a ground-floor garage to conditioned space, Title 24 envelope compliance kicks in for the new conditioned area. Pure structural retrofit (steel frames, moment connections) without changing conditioned space generally doesn't trigger Title 24.
Is the HERS rater requirement different in SF?
The state HERS requirement is the same, but the Bay Area has fewer qualified raters per capita than Southern California. Book early — at rough-in, not after drywall.
Does Title 24 require PV solar on SF remodels?
Major remodels that change more than 50% of the floor area trigger PV-mandatory (same as LA). SF's orientation and dense lot geometry often make rooftop PV impractical, in which case performance-path alternatives (community solar, battery storage) may substitute.
What CF forms does SF DBI require at final inspection?
CF-1R (filed at permit), CF-2R (filed at rough-in), and CF-3R (HERS verification, filed after mechanical completion). Missing any of the three delays Certificate of Occupancy. SF DBI does not issue partial COs.