Published July 1, 2026 · 6 min read
The short answer
We analyzed every residential project OC Solar completed in 2025 — 1,299 installations across Southern California. The median system was 8.0 kW. 70% included battery storage, up from the panels-only era — and among battery projects, 31% installed two or more batteries. Where a battery brand was recorded, 98% chose Tesla Powerwall. Composition shingle remains the most common roof we build on, and the busiest cities were Irvine, Simi Valley, and Huntington Beach.
By Vinnie Curcie, Founder & CEO
Why we published our install data
Most solar statistics online are national averages from surveys or marketplace quotes — not completed projects. This is different: it's an aggregate of every residential project OC Solar completed in calendar 2025, pulled from our own operations platform. No estimates, no extrapolation — 1,299 finished installations across Orange, Los Angeles, Riverside, San Bernardino, Ventura, and San Diego counties.
We're publishing it because the questions homeowners ask us most — how big should my system be, does anyone actually buy batteries, which battery do people pick — deserve answers grounded in real installations rather than calculator defaults.
Methodology
Population: all 1,299 residential projects marked completed in our operations platform with a 2025 completion date. System-size statistics use the 1,110 of those with a recorded array size; battery statistics use equipment records and line-item project scopes; roof-type mix uses recent completed projects with a recorded primary roof type (n=837, 2023–2026). Figures are aggregates of company records — individual projects vary, and none of this is a quote or a savings promise.
The median 2025 system: 8.0 kW
Half of our 2025 installations were 8.0 kW or larger. The full distribution: 23% under 6 kW, 38% between 6 and 9 kW, 22% between 9 and 12 kW, and 17% at 12 kW or larger. Total capacity completed in 2025: 9.6 MW.
The practical takeaway: if you've been quoted a 6–9 kW system for a typical Southern California home, that's exactly the range most of your neighbors actually built. Systems above 12 kW usually mean high usage — pool equipment, EVs, electric heat — or a battery-first design that banks extra daytime production.
| System size | Share of 2025 installs |
|---|---|
| Under 6 kW | 23% |
| 6–9 kW | 38% |
| 9–12 kW | 22% |
| 12 kW+ | 17% |
70% of 2025 projects included a battery
The single clearest signal in the data: batteries are no longer the upgrade — they're the default. 70% of our 2025 completions included battery storage. That is the NEM 3.0 effect in one number: with exported solar earning far less than it used to, storing daytime production for the expensive evening hours is where the savings moved.
It goes further: among projects that included storage, 31% installed two or more batteries — whole-home backup and bigger evening coverage, not just essentials. And where the battery brand was recorded in the project scope, 98% was Tesla Powerwall — a landslide that mirrors what Powerwall 3's integrated inverter did to system design economics.
What we build on: the roof mix
Across recent completed projects with a recorded roof type, composition shingle leads (about half), followed by concrete flat tile, concrete S-tile, flat/low-slope roofs, and clay tile. The mix matters because mounting differs by surface: shingle takes standard flashed attachments, tile calls for tile hooks or comp-out sections, and flat roofs use ballasted or tilt-up racking — all of which we design for in-house.
Where 2025's projects happened
The busiest cities in our 2025 completions: Irvine (53), Simi Valley (47), Huntington Beach (43), Santa Ana (42), Mission Viejo (40), Thousand Oaks (39), Los Angeles (38), and Lake Forest (36) — with the balance spread across more than 150 Southern California communities. Ventura County's strength (Simi Valley and Thousand Oaks both in the top six) reflects how far beyond Orange County the 2025 footprint reached.
What this means if you're going solar in 2026
Three things the data supports. First, size to your usage, not to a round number — the healthy middle of the market is 6–9 kW, but the 12 kW+ tier is real and growing with electrification. Second, price your project with a battery from the start; seven in ten of your neighbors did, and under NEM 3.0 the battery is usually what makes the math work. Third, if you want whole-home backup, you're not overbuilding — nearly a third of battery buyers went multi-unit.
Every number above comes from our own completed projects. If you want to see what a system sized for your actual roof and usage looks like, a free itemized estimate takes a few minutes.
FAQ
In OC Solar's 2025 completion data — 1,299 finished residential projects — the median system was 8.0 kW, with 38% of installs falling between 6 and 9 kW. National survey averages often quote 7–8 kW, and our completed-project data lands in the same range for real Southern California homes.
Sources
- 1.CPUC — Net Energy Metering and Net Billing (NEM 3.0) — California Public Utilities Commission · accessed 2026-07
- 2.SCE — Time-of-Use Residential Rate Plans — Southern California Edison · accessed 2026-07
- 3.Tesla — Powerwall — Tesla · accessed 2026-07
Incentives and rates change. This page is kept current — but always confirm specifics for your home.
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