How to Compare Solar Quotes in California: The 7 Numbers That Actually Matter

Adrian Marin|Independent Solar Advisor, Temecula CA

Helping Riverside County homeowners navigate SCE rates and solar options since 2020

Three quotes for the same Temecula home can vary by $10,000 to $15,000 and still be comparing fundamentally different products. Before you choose based on the lowest number, here is how to put quotes on equal footing.

Why Quotes Look So Different for the Same Home

Solar installers are not quoting the same system at different prices. They are quoting different systems entirely. The variables include system size in kilowatts, panel wattage, inverter type, financing assumptions, and warranty terms. A 6 kW system with Enphase microinverters and Panasonic panels at one price is not comparable to a 7 kW system with a SolarEdge string inverter and a budget panel brand at another price. The products are different. The production curves over 25 years are different. The risk profiles are different.

The goal of quote comparison is to normalize these differences so you can make a fair judgment. These seven numbers give you a framework for doing that.

The 7 Numbers to Compare

1. System Size in Kilowatts

The first number to confirm is total system size in kW DC. This is the sum of all panel wattages. A 20-panel system at 400W per panel is 8 kW. The same 20 panels at 350W is 7 kW. Panel count alone tells you nothing. Always check the wattage per panel and do the math.

Each installer's proposed system size reflects their estimate of how much generation you need to offset your SCE usage. If one installer proposes a 6 kW system and another proposes an 8 kW system, ask both to show you the SCE bill analysis they used. If they are targeting different offset percentages, the savings estimates will be incomparable.

2. Estimated Annual Production in kWh

This is the number that connects system size to your actual utility bill. Every quote should include a production estimate in kilowatt-hours per year. A well-designed 8 kW system in Temecula, with good solar access and south or west orientation, typically produces 12,500 to 14,000 kWh annually based on local irradiance data.

Compare this number across quotes. If one installer projects 16,000 kWh from an 8 kW system in Temecula, that estimate is almost certainly inflated. Inflated production estimates make the payback period and savings projections look better than they will be in practice.

3. Cost Per Watt

Divide the total system cost by the system size in watts. This is the single most useful number for comparing quotes across different system sizes.

California benchmarks for 2026:

• Under $2.50/W: warrants scrutiny. This typically means cheaper panels, a high dealer fee financing structure, or a system undersized for your usage. It is not automatically a bad deal, but understand what you are getting before signing.
• $2.50 to $3.50/W: competitive range for a quality residential system with a reputable panel brand and a standard warranty package.
• Above $3.50/W: should come with a clear explanation. Premium panel brands, complex roof geometry, a battery storage system included in the quote, or a 25-year workmanship warranty can each justify a higher cost per watt. If none of these apply, ask why.

4. Panel Brand and Warranty

Panel warranties have two components: the product warranty covering manufacturing defects, and the performance warranty covering degradation over time. The industry standard performance warranty guarantees 90 percent of rated output at year 10 and 80 percent at year 25. Premium manufacturers such as Panasonic, REC, and Maxeon guarantee 92 percent or better at year 25.

The brand matters for warranty claims, not just marketing. A panel manufacturer that goes out of business in year 12 leaves your warranty worthless. Focus on manufacturers with long track records and financial stability. Also verify whether the warranty is backed by the manufacturer directly or requires going through your installer, since the latter creates an accountability gap if the installer closes.

5. Inverter Type and Warranty

The inverter converts DC power from your panels into usable AC power. There are three main options, and the choice has real performance and cost implications.

• String inverters connect all panels in series to a single central inverter. They cost less and work well on simple, unshaded roofs. A single underperforming panel from shade or soiling drags down the entire string's output. Warranties are typically 12 years, extendable to 25 years for an additional cost.
• Microinverters attach to each panel individually, eliminating single-point failure. Each panel operates at its maximum regardless of neighboring panels. Enphase microinverters carry a 25-year warranty and are the market standard. They cost 15 to 20 percent more than string inverter systems. For Temecula homes with multiple roof planes or any shading from chimneys, trees, or adjacent structures, microinverters typically pay back the price premium over the system life.
• Power optimizers pair with a string inverter and attach to each panel, offering a middle ground in performance and cost. SolarEdge is the primary manufacturer. Panel-level monitoring is included. Performance is better than a plain string inverter on partially shaded roofs, at a lower cost than full microinverters.

Ask each installer to run a shade analysis for your specific roof using actual site data. The result should tell you whether your roof profile justifies microinverters or whether a string system is appropriate.

6. Installer Workmanship Warranty

The workmanship warranty covers the installation itself: roof penetrations, racking, wiring, and system integration. Panel and inverter manufacturers will not cover a defect caused by poor installation. The workmanship warranty fills that gap.

• 10 years is the baseline minimum for any installer worth hiring.
• 25 years is the gold standard and signals an installer confident enough in their work to stand behind it for the system's life.
• Ask explicitly whether the company performing the installation is the company signing the warranty, or whether installation is subcontracted. A subcontracted installation creates ambiguity in warranty claims.

7. Estimated Payback Period Assuming NEM 3.0

This is where the most common quote errors occur in 2026. Under California's NEM 3.0 tariff, which applies to all SCE customers who interconnected after April 2023, the utility pays roughly 8 cents per kWh for energy you export to the grid. That compares to the 28 to 34 cents per kWh you pay to import power, depending on your rate plan and time of use.

Under NEM 2.0, many homeowners received near-retail credit for exports. That program is closed to new customers. If an installer's quote projects $1,500 or more per year in export credits, ask them to show you the assumed export rate. A quote built on NEM 2.0 export assumptions will overstate savings for a new NEM 3.0 customer.

NEM 3.0 changes the optimal system design for many homes. Because exported power is worth far less than imported power, self-consumption becomes more valuable than overproduction. A correctly designed NEM 3.0 system prioritizes matching your usage profile with battery storage or time-of-use management, rather than simply maximizing panel output.

The Dealer Fee Trap

This is the most common source of hidden cost in solar quotes, and it is rarely explained upfront.

When a solar installation is financed through a solar loan, the lender pays the installer on closing and the homeowner repays the lender over the loan term. Lenders allow installers to charge a dealer fee, which is a markup typically ranging from 20 to 35 percent of the cash price. This markup is added to the amount the lender finances. It does not appear as a line item on most quotes.

A concrete example: a system with a cash price of $25,000 and a 30 percent dealer fee results in the lender financing $32,500. The homeowner repays $32,500 plus interest, not $25,000 plus interest. The dealer fee is the difference between the cash price and the loan amount, and it goes entirely to the installer. The homeowner gets nothing additional in exchange for it.

To identify the dealer fee, ask every installer two direct questions: "What is the cash price for this system?" and "What exact amount will the lender finance?" If the loan amount is 20 to 35 percent higher than the cash price, that gap is the dealer fee. A transparent installer will explain this without being asked.

Three Questions to Ask Every Installer Before Signing

After reviewing the seven numbers, three direct questions close most of the remaining gaps.

• "What is the cash price, and what amount will the lender actually finance?" The gap between these two numbers is the dealer fee. Any installer who cannot answer this directly is either uninformed about their own financing product or not disclosing it.
• "Does your savings estimate assume NEM 3.0 export rates, and what exact export rate per kWh is in your production model?" A confident answer is a good sign. Hedging or referring you back to a software output without explaining the assumption is not.
• "Is your company the actual installer, or will you subcontract the installation? And who exactly is backing the workmanship warranty?" A company that sells systems but subcontracts every installation to different crews has a different risk profile than one with in-house installers. Warranty accountability matters when something goes wrong in year 8.

These questions are not adversarial. A good installer will answer all three without hesitation and without treating you like a suspicious customer. If any of these questions produces deflection, that itself is useful information.

Putting It Together

Run every quote through the same checklist. Normalize cost per watt. Verify that annual production estimates are reasonable for Temecula's solar resource. Confirm the financing amount and identify any dealer fee. Check that savings estimates use NEM 3.0 export rates. Compare warranty terms side by side.

After this process, most homeowners find that two of three quotes are genuinely comparable and one stands out, either as unusually low with components that explain it, or as clearly the best-value product at a price they can understand. The goal is to make that judgment from a position of clarity rather than confusion.