In this guide
The short answer
A total price cannot tell you whether a solar quote is expensive. Start with the cash price for the same scope of work, separate batteries and roof work, then compare system size, production and contract terms. A smaller total is not automatically a better deal.
1. Start with the gross cash price
Ask for the installed cash price before incentives, alongside the financed price for the identical equipment and scope. A monthly payment can make two very different purchase prices look similar by stretching the repayment term.
The CFPB documented solar financing markups in its 2024 report. That does not tell you what your lender charges today. It gives you a reason to ask for an itemized explanation of any gap between cash and financed pricing.
2. Divide solar-only dollars by DC watts
Convert system size from kilowatts to watts, then divide the solar-only cash price by those watts. For example, $24,000 divided by 8,000 watts is $3.00 per watt. Do not divide a solar-plus-battery package price by panel watts and compare it with a panels-only quote.
Price per watt is a starting comparison, not a quality score or a universal fair-price threshold. Difficult roof work, installation scope and local conditions can legitimately change the cost.
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3. Separate the battery and other work
Ask for separate prices for storage, roofing, electrical-panel work, trenching and any service upgrade. For batteries, compare usable energy capacity, power output, backup circuits and installation scope. Two products described as “one battery” may deliver very different service.
4. Compare annual production assumptions
The same panel capacity can produce different amounts of electricity on different roofs. Ask for the orientation, shading and loss assumptions behind each annual kWh estimate. If one proposal predicts substantially more production from a similar layout, ask why.
A production forecast is not automatically a guarantee. Read the separate guarantee, if one exists, including exclusions, measurement rules and the remedy for underproduction.
5. Identify the equipment and warranty provider
Get panel and inverter model numbers, plus separate equipment, workmanship and roof-penetration terms. Ask who handles a service call, who pays labor, and what remains covered if the installer stops trading. A long headline warranty does not answer those questions.
6. Check the financing schedule
Compare principal, APR, term, upfront fees and the total of payments. Ask whether a later payment depends on making a lump-sum prepayment. A low initial payment is not a complete loan description. Use the actual written offer rather than an assumed market interest rate.
7. Make the savings illustration show its work
The illustration should identify the utility tariff, remaining grid purchases, export credits and fixed charges. Keep electricity-bill reduction separate from savings after loan payments and maintenance.
For a new 2026 installation, do not subtract the former 30% federal homeowner credit: the IRS says the credit is unavailable for property placed in service after December 31, 2025. Verify other incentives individually. If the comparison still feels unclear, request a second written proposal using the same assumptions.
Worked example: the lower total is not the lower price per watt
| Compare | Offer A | Offer B |
|---|---|---|
| Solar-only cash price | $24,000 | $21,000 |
| System capacity | 8 kW DC | 6 kW DC |
| Price per watt | $3.00 | $3.50 |
| Production and scope | Must be checked | Must be checked |
What to request in writing
- Gross cash price and financed principal for the same scope.
- DC system size, annual kWh estimate and shading assumptions.
- Battery and non-solar work itemized separately.
- Equipment models, service responsibility and warranty exclusions.
- Utility charges after solar and every financing payment.
Ready to check your own numbers?
Start with your home’s estimate. If you want a closer look, ask us to find an installer to verify the results and provide a written recommendation, price or savings illustration by email first. No sales call is required to request the introduction.
See my estimateContact details, including a phone number, are required only when you request an introduction. You can attach an electricity bill to help the installer verify usage. The bill is optional.
Related guides
Sources and assumptions
Examples on this page illustrate the comparison method; they are not installation quotes, financing offers or guaranteed savings. Use your current tariff and written proposal for a personal decision.
- CFPB: Solar Financing, August 2024 — fees and payment structures
- IRS: Residential Clean Energy Credit — current installation deadline
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