Average Wattage of a Commercial Solar Panel: What California Data Shows

A commercial solar panel installed in California in 2025 was rated at about 440 to 460 watts. Across the non-residential systems PG&E, SCE and SDG&E connected that year, the median module was 438 W, against 370 W on homes, and systems over 100 kW used about 504 W. New models on the state equipment list run higher still, at a median of 550 W.

No agency publishes an “average commercial panel” figure, so CRR computed these from two public datasets: the CPUC's interconnection records and the California Energy Commission's PV module list. The method is at the foot of the page. For what the systems cost, see commercial solar cost per watt in California; for every business guide, the commercial solar hub. Data checked September 23, 2026.

What California businesses actually installed

The CPUC's DGStats interconnection file lists each system's DC size and its module counts. Dividing one by the other gives the watts per module. For systems connected in 2025:

By customer sector, the 2025 medians were 424 W for commercial customers, 498 W for industrial, 507 W for schools and colleges, 458 W for government and 413 W for nonprofits. The trend is upward: the non-residential median was 401 W for systems connected in 2024 and 482 W for those connected from January through May 2026.

Project size drives most of the gap. Business systems of 100 kW or less sit close to home systems, at a 405 W median. Past 100 kW the median jumps to about 500 W, which is where the larger module formats in the next table come in.

Bigger panels, not better cells

The Energy Commission's PV Module List gives each model's nameplate rating and its surface area, so you can see where the extra watts come from. Among the 1,651 non-building-integrated models added in the year to September 21, 2026, from 75 manufacturers:

Efficiency barely moves across the sizes, which means a 590 W panel is not a better panel than a 440 W one. It is a larger one, around 2.5 square meters against 2. The median across all 1,651 models was 22.7%.

Efficiency itself keeps rising slowly. Berkeley Lab's 2026 data update finds median module efficiencies have risen about 0.4 percentage points a year over the long term, and its Tracking the Sun 2024 report found the rise in both residential and non-residential systems.

One caution on these counts: each power rating in a product family is listed as its own model, so the table weights families with many ratings. It shows what is available, not what sold. The installed figures in the first table are the better guide to a typical project.

The trend in new models

The median rating of models added to the Energy Commission list has climbed each year: 420 W for models listed in 2022, 445 W in 2023, 535 W in 2024, 545 W in 2025 and 565 W so far in 2026. Installed systems lag the list, because projects are designed months before they are connected.

What wattage means for your project

Panel count. A system's size is watts per panel times the number of panels. A 100 kW DC array takes about 227 panels at 440 W, or about 170 at 590 W. A 500 kW array takes about 1,136 or 848.

Roof fit. Larger panels mean fewer mounts and connections, but the roof has to suit the format. Setbacks, fire pathways, rooftop equipment and structural capacity decide how many fit, and a larger panel can leave more unused space around obstructions. The commercial roof guide covers those limits.

Rated output versus real output. Nameplate watts are measured at standard test conditions. The Energy Commission notes that its PTC rating, calculated at conditions closer to the field, is lower than the nameplate and “generally recognized as a more realistic measure of PV output,” and that actual systems produce less again after soiling, wiring, inverter and heat losses. Compare proposals on modeled annual kilowatt-hours, not on panel wattage.

Price. Quotes are priced per watt of the whole system, not per panel. The commercial cost benchmarks give the published per-watt figures, and the commercial solar tax credit guide covers the credit that applies to that cost.

What to check on a commercial proposal

• The exact module model, and its listing on the Energy Commission equipment lists.
• Its nameplate and PTC ratings, dimensions and efficiency, from the list rather than a brochure.
• The DC system size, the number of modules, and the AC inverter capacity.
• The modeled first-year production and the degradation rate the model assumes.
• Whether the racking and roof structure were checked for the module's size and weight.

If a bidder proposes a specific brand, the REC commercial panel guide shows how to read one manufacturer's listings, and comparing commercial solar companies covers the rest of the bid.

Frequently asked questions

California Rate Relief is a referral service. We are not a licensed contractor. It does not sell or recommend any module brand.

How these figures were calculated

Installed modules. From the CPUC DGStats Interconnected Applications file (PG&E, SCE and SDG&E; data through May 31, 2026), CRR took photovoltaic applications with status Interconnected and an approval date in 2025, and divided each system's DC size by its total module count. Systems with a result outside 150 to 800 W were treated as data errors and dropped, which kept 3,391 of 3,607 non-residential systems. Non-residential means the commercial, industrial, educational, nonprofit, government and military sectors. Municipal utilities such as LADWP and SMUD are not in this file.

Listed models. From the CEC PV Module List full data (marked “Data has not changed since September 21, 2026”), CRR took non-building-integrated models with a listing date from September 21, 2025 to September 21, 2026. Efficiency is the nameplate rating divided by the listed module area times 1,000 W per square meter.

Sources

Checked September 23, 2026.

• California Public Utilities Commission, California Distributed Generation Statistics, Interconnected Applications Data Set (data through May 31, 2026)
• California Energy Commission, PV Module List, full data (unchanged since September 21, 2026), and Solar Equipment Lists
• LBNL, U.S. Distributed Solar and Storage: 2026 Data Update (August 2026) and Tracking the Sun 2024 (October 2024)