California Climate Zone 15 is one of the 16 official climate zones the California Energy Commission uses to set Title 24 energy budgets. Title 24 is a statewide California energy code. Climate Zone 15 does not have its own separate rules — the same statewide standards apply, with the energy budget calibrated to this zone's climate. Your project's exact requirements are determined when your specific address is modeled in CEC-approved compliance software.
What Climate Zone 15 means
Each of California's 16 zones reflects distinct temperature, humidity, and solar conditions, and each has its own energy budget under Title 24. Climate Zone 15 is one of them.
Why Climate Zone 15 matters for Title 24
Although the standards are statewide, the budget your design must meet is calibrated to the zone — which can shift the emphasis between insulation, HVAC, windows, and solar. The exact targets are determined when your address is modeled.
The Climate in Zone 15 and What It Means for Your Report
Climate Zone 15 covers California's low desert, including the Coachella Valley cities of Palm Springs and Indio. It is the hottest zone in the state: summers are long and extreme, sunshine is intense, and winters are mild enough that heating is a small part of the picture.
Cooling dominates the energy model in Zone 15 more than anywhere else in California. Window solar heat gain, glass area and shading, roof and attic design, and ducts located in hot attics have a large effect on compliance, and the cooling efficiency of the heat pump or air conditioner is critical. Measures that keep summer heat out of the building usually matter far more than winter-focused upgrades.
Cities & areas in Climate Zone 15
Climate zones are assigned by exact project address — often by ZIP code — and a single city can span more than one zone. The cities named on this page are examples only; we always confirm your zone from your project address. Browse our city Title 24 pages or read how cities map to Zone 15.
California Title 24 Climate Zone 15. Your project's zone is set by its address; see the California Energy Commission's official climate zone map for boundaries.
How Zone 15 affects HVAC
The zone's climate influences how heating and cooling are weighted in the model. Current Title 24 favors heat pumps statewide. Zone 15 HVAC requirements →
How Zone 15 affects windows
U-factor and SHGC targets are influenced by the zone's climate. Zone 15 window requirements →
How Zone 15 affects insulation
Wall, roof, and floor performance is measured against the zone's energy budget. Zone 15 insulation requirements →
How Zone 15 affects solar & heat pumps
Solar PV is required for most new low-rise residential statewide, with PV size set by your project; heat pumps are favored under current code. Solar & battery → · Heat pumps →
Common project types
Looking for a specific address? See every city and ZIP code in Climate Zone 15, taken from the California Energy Commission's official table, or use the climate zone ZIP code lookup.
Title 24 Guides for Climate Zone 15
Begin with the Climate Zone 15 Title 24 requirements overview, then read Zone 15 HVAC requirements, Zone 15 window requirements and Zone 15 insulation requirements, the systems that desert heat puts under the most pressure. The Zone 15 heat pump guide and Zone 15 ADU guide cover equipment and backyard units, and Title 24 cost in Zone 15 covers pricing. For statewide background, see California Title 24 requirements and Title 24 calculations. City guides include Palm Springs and Indio.
Climate zones follow the project address, not just the city name, and one city can straddle two zones. We confirm the exact zone from your address or ZIP code when we model the project; you can also check it yourself with our California climate zone lookup.
Title 24 pricing
- ADU — from $199
- Residential — from $245
- Multifamily — from $345
Standard turnaround: 2–3 business days. Rush (next business day): +$49 ADU / +$99 Residential / +$149 Multifamily. Super Rush (same day — typically completed within a few hours): +$150, subject to availability. Every report includes two revisions. See our pricing page.
What we need
- Architectural plans (PDF)
- Project address (this determines your climate zone)
- Scope of work
- Contact information
- Any plan-check comments (if available)
What we deliver
- Complete Title 24 energy report
- CF1R documentation (LMCC when applicable)
- CHEERS registration completed
- Professionally signed, permit-ready PDF package
- Two Revisions Included