Solar Panel Cost by System Size in California (2026)

Why size drives the price (it's per-watt)

California installers price solar by system size in watts (W) or kilowatts (kW), at a price per watt. So a bigger array costs more in near-linear fashion: double the kilowatts and you're roughly doubling the panel and labor cost. The per-watt figure for residential solar in California commonly lands somewhere around $2.50–$3.50 before financing, which is the number we use to sketch the size tiers below.

Treat everything here as an estimate, not a quote. Per-watt pricing varies with equipment tier, roof type, and electrical scope, and none of these tiers include battery storage — which under NEM 3.0 you'll almost always want. The only accurate number is an itemized proposal built from your roof and usage. Shopping in OC? See our county-level breakdown of solar panel cost in Orange County, built on cited local market data.

6 kW: smaller homes and modest usage

A 6 kW system suits smaller homes, lower electricity usage, or roofs with limited usable space. At a rough $2.50–$3.50 per watt, that's an estimated $15,000–$21,000 before financing and before any battery. It's enough to offset a meaningful share of a modest bill, but under NEM 3.0 the savings still hinge on pairing it with storage so you use your own power in the evening rather than exporting it for a low credit.

8 kW and 10 kW: the typical range

Most California single-family homes land in the 8–10 kW range. An 8 kW system runs an estimated $20,000–$28,000 before financing; a 10 kW system roughly $25,000–$35,000. These sizes cover the usage of a typical home with central AC and normal appliance loads, and they're the band where a properly sized battery does the most work — banking midday production for the expensive 4–9 PM peak.

Bigger isn't automatically better. Under NEM 3.0, oversizing the array to export surplus power earns very little, so the smarter design covers your usage and charges a battery rather than piling on panels you'll mostly give away to the grid.

13 kW: larger homes, EVs, and heavy loads

A 13 kW system fits larger homes, all-electric households, or homes with EV charging and heavy air conditioning. At a rough per-watt rate, that's an estimated $32,000–$45,000 before financing and before storage. At this size, electrical work — a main-panel upgrade or sub-panel for backup loads — becomes more likely, which is part of why larger systems can carry a slightly different per-watt math than the small tiers.

What moves your number within a tier

Two homes at the same kilowatts can land at different totals. The biggest swing factors are panel and inverter tier, whether you add battery storage (and how much), roof complexity — tile is more labor than composition shingle, and multi-plane or steep roofs cost more — and electrical upgrades like a panel swap. Because NEM 3.0 makes a battery essential for most homeowners, the realistic 'all-in' figure is higher than these panel-only tiers suggest, which is exactly why we itemize storage separately so you can see each piece.

How financing changes your out-of-pocket

These tiers describe the system price, not what you pay up front. Pay cash and you own the system outright with the fastest payback. Take a solar loan and you spread the purchase over time — but note the federal §25D residential tax credit that used to offset 30% of a cash or loan purchase expired December 31, 2025, so loan buyers no longer receive it. Or choose a $0-down lease or PPA, where the financing company owns the system, claims the commercial §48E credit through roughly 2027, and passes that value to you as a lower monthly payment — so your out-of-pocket at signing can be nothing regardless of which size tier you're in.