Cities & areas in CZ3
San Francisco, Oakland, Berkeley — and the surrounding ZIP codes mapped to Climate Zone 3 by the California Energy Commission. If you're not sure which zone applies to your project, the ZIP-code lookup tool will tell you.
Prescriptive baseline for CZ3
These are the values your project's design has to meet — or beat — under the Title 24 Part 6 prescriptive path. Your CF1R can also satisfy compliance through the performance path; the values below are what the code book sets as the baseline for CZ3.
| Component | Value |
|---|---|
| Ceiling | R-30 (R-30 Ceiling Below Attic) |
| Walls | R-15+R4 CI, 2x4, Synthetic Stucco |
| Roof assembly | Asphalt Shingle, Radiant Barrier |
| Radiant barrier | Required |
| Window U-factor | U-0.27 |
| Window SHGC | 0.35 |
| Heating & cooling | Heat pump · HSPF2 9.5 / SEER2 17.0 / EER2 13.0 |
| Water heating | Heat-pump water heater (Tier 4 50-gallon HPWH) |
What this means for your design
In practice, walls stay at 2x4 R-15 with continuous-insulation sheathing on the outside, the roof needs a radiant barrier on the underside of the deck, windows target SHGC 0.35, the heat pump needs HSPF2 9.5 / SEER2 17.0.
ADUs and additions in CZ3
Accessory Dwelling Units, additions, and addition+alteration projects in CZ3 run against the same per-zone baseline shown above, with scope-specific adjustments — newly-constructed dwellings get full PV sizing; additions and alterations on a permitted residence are exempted from PV. The flow on this site picks the right scope automatically based on the details you confirm.
Title 24 reports in CZ3 cities
Detailed pages for the largest cities in CZ3 — same prescriptive baseline as above, plus the local building department that will receive your submitted CF1R:
Title 24 in San Francisco · Title 24 in Oakland
The three design options for CZ3 projects
Whether your design lands in CZ3 or anywhere else in California, you'll choose between three pathways: Prescriptive (matches the baseline above), 2x4 Performance (lighter framing, compensated by upgraded windows and roof), and 2x6 Enhanced (heavier framing, easier equipment specs). Full breakdown on the Title 24 explained page.
Other California climate zones
Title 24 prescriptive values change zone by zone. Browse the full set:
CZ1 · CZ2 · CZ4 · CZ5 · CZ6 · CZ7 · CZ8 · CZ9 · CZ10 · CZ11 · CZ12 · CZ13 · CZ14 · CZ15 · CZ16