ADU Solar Cost by System Size
- 2 kW — 400–600 sq ft ADU (Title 24 minimum for most CZ 6/8/9 ADUs) · Cash $4,000–$5,500
- 3 kW — 500–800 sq ft ADU — typical Title 24 sizing for most California ADUs · Cash $5,500–$7,500
- 4 kW — 800–1,000 sq ft ADU or larger ADUs in CZ 10/13/14/15 · Cash $7,000–$9,500
- 5 kW — 1,000–1,200 sq ft ADU with electric heating + EV charging · Cash $8,500–$11,500
- 6 kW — 1,200 sq ft+ ADU or main-house + ADU combined offset · Cash $10,000–$13,500
- 8 kW — Main-house + ADU combined system covering full household electric + EV · Cash $13,000–$17,500
- 10 kW — Maximum residential interconnect for most utilities — full electrification · Cash $16,000–$22,000