Every newly constructed detached ADU in San Diego County, California must include a Title 24-compliant solar PV system. San Diego County spans climate zones 7, 10, 14, which determines exactly how many kilowatts your specific project must install for code compliance.
Local building departments across San Diego County enforce Title 24 at plan check. Plans submitted without a properly sized solar system are routinely rejected unless a documented exemption (shading, roof area, structural) applies.
San Diego County pioneered many ADU-friendly policies. With SDG&E's high electricity rates, solar-equipped ADUs offer substantial utility bill savings. The county spans coastal, inland, and mountain climate zones.
Title 24 multiplies your ADU's conditioned floor area by a climate-zone-specific kW factor. Across San Diego County's climate zones 7, 10, 14, most ADUs land in the 1.6–4.0 kW range — typically 4 to 10 modern (~400W) panels.
Title 24-compliant ADU solar packages range from $4,000 (Standard cash) to $15,000+ (Premium with battery) across San Diego County. HDM financing typically reduces effective cost by ~40% via commercial ITC pass-through. Main utilities serving the county: SDG&E.
Yes. Title 24 is California state law and every jurisdiction in San Diego County enforces it at permit submittal.
San Diego County sits in climate zones 7, 10, 14. Use our cost calculator to map your exact ZIP code to its Title 24 climate zone.
Exemptions are project-specific, not countywide. The most common are shading (<70% annual solar access), insufficient roof area, and structural infeasibility. Your designer documents these on the CF1R compliance form.