How to Compare California Solar Proposals

Begin with the same household information

Give each company the same complete electric-bill history, service address and description of planned loads. Twelve months of usage is more useful than one high bill because cooling, heating, travel and seasonal solar production vary. Identify an existing electric vehicle, pool, heat pump or electric water heater, and separate current loads from future plans. A proposal that assumes a future EV while another uses only present consumption is not an equal comparison.

Confirm the utility, rate schedule, Community Choice Aggregator when applicable and current solar-program status from the bill. Do not substitute a city average or a neighbor’s rate. Ask the proposer to record the annual kilowatt-hours used, any load growth added and the source of the tariff assumptions. If an estimate cannot show these inputs, its projected bill result cannot be reproduced or fairly compared.

Normalize system size, equipment and included scope

Put the proposed DC system size in kilowatts, module model and quantity, inverter architecture, battery model, usable energy and power rating into one comparison table. Two proposals with similar monthly payments may deliver different array sizes or battery capability. A higher-efficiency panel can help on a constrained roof, but the model number, layout and annual production estimate matter more than a brand name by itself.

List the work included in the quoted amount: design, engineering, permits, interconnection, monitoring, mounting, electrical upgrades, trenching, roof correction, main-panel work, backup-load controls and removal or reinstallation if roof work is expected. Mark every allowance, exclusion and condition that can lead to a change order. Compare like with like before using price per watt; do not divide a combined solar-and-battery price by solar watts and treat the result as a panel-price comparison.

Test the production estimate instead of accepting one number

Annual kilowatt-hours are an estimate, not a guaranteed meter result unless a written agreement expressly provides a production commitment and remedy. Ask for the roof layout and the assumptions for orientation, tilt, shade, soiling, temperature, inverter losses, clipping, equipment availability and degradation. Confirm whether the model uses preliminary satellite imagery or a completed site assessment.

The government-supported PVWatts calculator can estimate grid-connected photovoltaic production from system size, module type, array type, system losses, tilt, azimuth and weather data. It is useful as an independent reasonableness check, not a substitute for engineering or a promise that a particular roof will produce the modeled amount. When proposals differ materially, compare their input assumptions and ask each company to explain the gap in writing. A larger estimate is not automatically a better design.

Compare imports, exports and remaining utility charges

Solar production and utility-bill savings are different calculations. A home can export energy at one value and later import energy at another. Time-of-use periods, fixed charges, non-bypassable charges, Community Choice generation and the household’s hourly consumption pattern can all affect the result. Ask the proposal to separate expected onsite use, battery charging, exports and grid imports rather than applying one retail price to every projected solar kilowatt-hour.

Keep historical utility-rate changes, an individual household forecast and a contract escalator separate. A sales model should disclose the starting rate, rate-increase assumption, analysis period and whether the model assumes the customer changes rate plans. No company can guarantee future utility rates. Compare proposals once with the same conservative assumptions and again without a speculative utility inflation rate; that reveals how much of the claimed savings depends on the forecast.

Evaluate battery design as power, energy and operating purpose

A battery proposal should state usable kilowatt-hours, continuous power, surge or load-start capability when relevant, reserve setting, supported circuits and whether solar can recharge the battery during an outage. Energy capacity describes how much can be stored; power describes how much can be delivered at once. Neither number alone establishes backup duration. Ask for a circuit-level load plan and the assumptions used for outage estimates.

Also identify the normal operating purpose. A battery reserved for outages behaves differently from one dispatched every evening to reduce grid imports or respond to hourly export values. Compare round-trip losses, operating reserve, warranty term, throughput or cycle limits, placement requirements and service responsibility. If one proposal includes whole-home controls and another supports only selected loads, their battery counts are not an equivalent comparison.

Identify every legal party and verify the contractor

The company that markets a project may be different from the licensed installation contractor, finance company, system owner, equipment manufacturer and service provider. Write down each legal name and its exact role. The final documents should identify who designs, permits, installs, owns, monitors, services and warranties each part of the project. A manufacturer logo or authorized-sales relationship does not make an independent sales organization the installer.

Use the California Contractors State License Board’s official license search to verify the contractor’s license number, classification, status, bond and workers’ compensation information shown in the record. Ask for the home-improvement salesperson registration when applicable and verify it against the named employing contractor. Review the record again before work begins because status can change. A valid license does not prove that every proposal term is favorable, but an unverifiable or mismatched contractor identity is a reason to stop.

Compare cash, loan, lease and PPA economics separately

Start with the complete cash price for the same equipment and scope. For a loan, record the amount financed, annual percentage rate, term, monthly-payment schedule, lender fees or dealer-related price differences, prepayment terms and any payment change tied to an expected voluntary prepayment. The Consumer Financial Protection Bureau has warned consumers to examine solar-loan costs and complex payment structures rather than relying on a low opening payment. Never assume a tax credit will be received or automatically applied to a loan.

For a lease, record the fixed or escalating payment, term, service obligations, transfer process, purchase options and end-of-term choices. For a power purchase agreement, record the starting price per kilowatt-hour, escalator, production terms, billing method, transfer rules and remedies. Zero upfront means no upfront equipment payment under a qualifying offer; it does not mean free electricity or no contract. Compare the total scheduled payments, remaining utility charges and ownership outcome for each structure.

Read the proposal and every controlling agreement

A slide deck, savings illustration or email summary is not the complete transaction. Read the proposal, installation or home-improvement contract, loan agreement, lease or PPA, utility authorization, privacy permissions and warranty documents that apply. The CPUC’s current California Solar Consumer Protection Guide is designed to be read before signing and explains consumer rights and questions. CSLB also publishes solar contract and disclosure requirements.

Check the legal customer name, property address, cancellation rights, payment milestones, project schedule language, change-order procedure, default provisions, lien or security-interest terms, dispute process and electronic-signature record. Save the version you sign and all attachments. Do not rely on a verbal promise that conflicts with the documents. If a term is unclear, pause and obtain a written explanation; for legal or tax advice, consult an appropriately qualified professional rather than a salesperson.

Separate product, workmanship and provider obligations

Request the exact module, inverter and battery warranty documents, plus the installation contractor’s workmanship or roof-penetration coverage and any lease or PPA service commitment. These protections come from different parties and can have different start dates, exclusions, transfer rules and remedies. A 25-year module performance warranty does not automatically cover labor, diagnosis, roof leaks, an inverter or a battery.

Create a service map that names the first contact for monitoring alerts, equipment failure, roof concerns, billing questions and warranty claims. Ask who pays for truck rolls, removal, shipping, labor and reinstallation when a covered component is replaced. For a third-party-owned system, read the provider’s monitoring, maintenance and production obligations. For an owned system, identify which costs remain with the homeowner after each warranty expires.

Check project milestones, transfer rules and exit options

Permitting, installation, inspection and utility permission to operate are separate milestones. A local permit approval does not authorize grid operation, and an estimated schedule is not a guarantee unless the agreement says so. Ask what happens if engineering changes the design, the roof or service panel needs work, equipment is substituted, the utility requires corrections or the project is delayed. The change-order and cancellation provisions matter as much as the target installation date.

If the system will be financed or third-party owned, review a future home sale before signing. Identify the transfer process, buyer qualification, prepayment or purchase options, notice requirements, fees and end-of-term choices. Do not assume a system can be bought at a fixed future discount unless the agreement states that calculation. Keep transfer and service contacts with the property records so a future buyer does not have to reconstruct the transaction.

Use reviews and references with the right context

Reviews can reveal communication, installation and service patterns, but they should be connected to the actual legal entity and stage of work. Distinguish a review written after a sales meeting from one written after permission to operate or a later service event. Note the date, location, equipment and whether the reviewer is discussing the sales organization, contractor, manufacturer or finance provider. A national brand rating does not prove the timing or quality of the crew assigned to a particular home.

Look for detailed recent accounts across more than one source, including critical reviews and company responses. Do not treat anonymous excerpts, incentives or a perfect average as sufficient proof. If references are offered, use only permission-based contacts and ask about scope changes, schedule communication, inspection, activation and service. Reviews complement license records, contracts and technical documents; they do not replace them.

Build a one-page decision sheet before signing

For each proposal, record the system size, equipment models, estimated first-year production, production-model assumptions, battery capability, utility assumptions, included work, cash price or contract payment, escalator, total scheduled cost where available, warranties, legal parties, contractor license, expected milestones and unresolved questions. Mark every field that is missing instead of filling it with a guess.

Then compare the offers using the same load, rate and inflation assumptions. Reject any result that depends on guaranteed savings, guaranteed utility increases, an unapproved incentive or undocumented work. The purpose of the sheet is not to choose the lowest number automatically. It is to reveal whether the proposal fits the roof, household goals and risk tolerance and whether the written agreements support what was presented. Keep the completed sheet with the signed documents and update it when the design or price changes.

Apply this to your California home

Compare the matching $0 down solar in California page, the Axia by Qcells pathway and Qcells equipment. Local permit and utility questions are covered in our Irvine, Anaheim and Orange County pages.