Climate Zone 11 (Northern Central Valley) — ADU Solar & Title 24 Sizing

What Climate Zone 11 Means for ADU Solar Sizing

Title 24 multiplies your ADU's conditioned floor area by a climate-zone-specific kW factor to set the minimum required solar system size. Hot dry summers and cold winters with strong solar resource (~1,750 kWh/kW/year).

Most ADUs in Climate Zone 11 land in the 2.0–4.4 kW range — typically 4 to 10 modern (~400W) panels.

• 400–600 sq ft ADU: usually 1.6–2.4 kW (4–6 panels)
• 600–900 sq ft ADU: usually 2.4–3.2 kW (6–8 panels)
• 900–1,200 sq ft ADU: usually 3.2–4.0 kW (8–10 panels)

Solar Production in Climate Zone 11

Annual solar production in Climate Zone 11 is driven by local irradiance, temperature, and shading. Hot dry summers and cold winters with strong solar resource (~1,750 kWh/kW/year). Expect roughly 1,400–1,700 kWh per installed kW per year for typical south-facing roofs.

ADU Solar Cost in Climate Zone 11

Title 24-compliant ADU solar packages range from $4,000 to $15,000 in Climate Zone 11. Pricing is driven primarily by system size, panel quality, and battery — not climate zone itself. HDM financing typically reduces effective cost by ~40%.

FAQs

What cities are in Climate Zone 11?

Climate Zone 11 (Northern Central Valley) covers Red Bluff, Chico, Marysville. The California Energy Commission publishes the full ZIP-to-zone mapping.

Does Climate Zone 11 require a larger solar system?

Climate zones with hotter summers or more cloud cover tend to require slightly larger systems per square foot. Climate Zone 11 ADUs typically need 2.0–4.4 kW.

Can I look up my exact climate zone?

Yes — enter your ZIP code on our solar cost calculator. We map every California ZIP to its Title 24 climate zone automatically.