How to Compare Two Solar Quotes: The 20-Number Checklist
Straight answer: don't compare solar quotes on the monthly payment. Compare them on price per watt and the total 25-year cost. Two proposals for the same panels can differ by thousands once you add interest and a hidden dealer fee. Below is a 20-line checklist — the exact numbers to line up side by side, the red flags on each, and your right to cancel in California.
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- Compare quotes on price per watt and total 25-year cost — never the monthly payment alone.
- Financed deals often bury a dealer fee of 15–30% in the price; the same panels cost more than a cash quote.
- In California you can cancel a contract signed at your home within 3 business days (5 if you're 65 or older) — in writing, no penalty.
The one number that actually compares two quotes
Many quotes lead with a monthly payment because it's the easiest number to make look small — stretch the loan, roll in a fee, add an escalator, and "$0 down, $189/mo" can hide a system that costs far more than it needs to. The honest comparison is price per watt: take the all-in system price and divide it by the system's size in watts (DC). In California in 2026 a fair owner-bought price is about $2.60–$3.50 per watt before incentives. Then check the total cost over 25 years — the sum of every payment you'll actually make. Those two numbers, side by side, tell you which quote is really cheaper.
The 20-line quote-comparison checklist
Print this and fill in both columns for each quote. Ask for every line in writing — a clear, itemized proposal makes the comparison easy. The one row to weight above all others is highlighted.
| Line item | What to check | Red flag |
|---|---|---|
| Price per watt ($/W) | All-in system price ÷ system size in watts (DC). Compare this, not the monthly payment. | Below ~$2.60/W (cut corners or bait) or above ~$3.50/W (worth an itemized explanation). |
| System size (kW DC) | Confirm both quotes are sized in DC watts for the same offset of your usage. | One quote quietly smaller — "cheaper" only because it's less system. |
| Panel brand & model | Get the exact make and model, not just "premium panels." | Blank, "or equivalent," or a name with no findable datasheet. |
| Panel wattage | Watts per panel (e.g. 400–440 W) and the panel count. | Vague "high-efficiency" with no number, or a count that doesn't match the kW. |
| Panel product warranty (yrs) | Product/workmanship warranty on the panel itself — separate from the 25-yr performance warranty. | Under 12 years, or only the performance warranty listed. |
| Inverter type | Microinverters vs. a string inverter — affects shading, monitoring, and cost. | Type not stated, or a string inverter priced like premium micros. |
| Inverter brand & warranty | A named brand (Enphase, SolarEdge, etc.) with its own warranty term. | No brand, or a warranty far shorter than the panels'. |
| Year-1 production (kWh) | Estimated first-year output. Similar systems should predict similar kWh. | An inflated number used to promise savings the roof can't deliver. |
| Production guarantee | A written guarantee of stated kWh, with a make-good if it falls short. | "Estimates only," no guarantee, verbal promises. |
| Annual degradation % | Rate the panels lose output each year (~0.4–0.5% is good). | Above ~0.7%/yr, or not disclosed at all. |
| Cash price | The all-in price if you paid cash today — the cleanest number to compare. | Installer won't give a cash price, only a monthly payment. |
| Financed total cost | The sum of every payment over the loan — not the sticker price. | Financed total thousands above the cash price for the same system. |
| APR | The loan's annual percentage rate, in writing. | A "0% APR" whose cost is hidden in a higher system price (see dealer fee). |
| Dealer / financing fee | The fee the lender charges the installer to buy down the rate — usually rolled into your price. | a financing fee reflected in a cash price noticeably below the financed one. |
| Monthly payment | Useful only after you've checked price per watt and total cost. | Sold on the monthly payment alone, with no total or $/W shown. |
| Annual escalator % (lease/PPA) | For leases and PPAs, the yearly rise in your payment (often 2.9–3.9%). | Any escalator you weren't told about; payments that outrun utility rates. |
| Battery included? | Whether a battery is in the price, plus its brand and usable kWh. | "Battery-ready" sold as if a battery is actually included. |
| Main-panel upgrade included? | If your service panel needs upgrading, is it in the price or extra? | Not addressed, then billed as a change order after you sign. |
| Roof, permit & interconnection | Roof repair/replacement, the permit, and utility interconnection — in scope or extra? | "Permit not included," or roof condition ignored on an old roof. |
| Workmanship / labor warranty (yrs) | The installer's own labor warranty on the install and roof penetrations. | Under 10 years, or only manufacturer warranties (which don't cover labor). |
Fair-price ranges from EnergySage California cost data and SolarReviews. For the full price-per-watt breakdown, see what solar really costs in California in 2026.
Why price per watt and 25-year total beat the monthly payment
A monthly payment is not a price — it's a price stretched over time with interest added, and it can be tuned to look like anything. Lengthen the loan from 15 to 25 years and the payment drops even though you pay far more in the end. That's why the payment is the last thing to compare, not the first.
Price per watt strips all of that away. Same math for every quote: all-in price divided by system watts. It instantly tells you whether you're inside the fair California band (about $2.60–$3.50/W in 2026) or being overcharged. Then run the total 25-year cost — add up every payment, including any escalator on a lease. A quote with a lower monthly payment but a higher 25-year total is the more expensive quote, full stop. Whether solar pays off for your home at all is a separate question we work through in is solar still worth it in California?
Why the "0% APR" financed quote costs more
Solar lenders charge the installer a dealer fee to offer a low or "0%" rate — sometimes a substantial share of the price — in financing examples we’ve reviewed, roughly 15–30%. That fee is typically rolled into your price rather than absorbed by the installer. So the same panels that cost, say, $18,000 in cash can be written up to $23,000 on a financed deal to cover the fee. The tell: ask for the cash price and the financed price for the identical system. A large gap may reflect a lender dealer fee, a rate-buydown cost, or other financing charges — ask for a written breakdown. You're usually better off with a lower-price cash or plain-loan deal than a "0%" offer with a large financing fee included.
Your right to cancel in California
If a contract was signed at your home — the classic door-to-door or in-home solar pitch — California's Home Solicitation Sales Act gives you a cooling-off period to cancel in writing, with no penalty and no reason required. Under current law you have 3 business days to cancel — and 5 business days if you're 65 or older. The seller must give you written notice of this right and, if you cancel, return anything you paid within 10 days.
Practically: never sign under "this price is only good today" pressure. A legitimate installer's number is good next week too. Use the cooling-off period to run both quotes through the checklist above — and if you signed something you shouldn't have, you have days, in writing, to walk away.
Get a straight, itemized quoteSix items that deserve a clear answer
Payment-only pitch
They'll show a monthly payment but not the cash price, total cost, or price per watt. If you can't get all three in writing, that's the flag.
Vague equipment
"Premium panels" and "high-efficiency" with no brand, model, or wattage. Good installers name the exact gear because they stand behind it.
Cash vs. financed gap
A financed price thousands above the cash price for the same system. That gap is the dealer fee — and it's yours to pay.
Inflated production
A first-year kWh estimate well above a similar-sized quote, used to promise savings your roof can't actually produce.
"Today only" pressure
Urgency and same-day discounts exist to stop you comparing. Real pricing survives a night's sleep and a second quote.
Scope left out
Roof condition, a main-panel upgrade, or the permit missing from the quote — then billed later as change orders after you've signed.
Three moves that settle most comparisons
1. Compute price per watt for each quote (price ÷ watts) and see which sits inside $2.60–$3.50/W. 2. Ask both installers for the cash price next to the financed price — the gap reveals the dealer fee. 3. Add up the total you'll pay over 25 years, escalators included. The quote that wins on those three usually wins outright — regardless of whose monthly payment looked smaller.
Cash vs. financed vs. lease — how each hides cost
Cash is the cleanest and lowest lifetime cost: you pay the sticker and own the system, so price per watt tells you almost everything. A solar loan is fine — just separate the true system price from the interest and any dealer fee rolled in; compare the cash-equivalent price, not the payment. A lease or PPA means a third party owns the panels: little up front, but watch the annual escalator, the buyout terms, and how it complicates selling your home. If your bill went the wrong way after going solar, that's usually sizing or rate-plan math, not the panels — we unpack it in why your bill went up after solar. Whichever route you choose, the checklist is the same: real equipment, real price per watt, real 25-year total.
Frequently asked
What's the single best way to compare two solar quotes?
Compare price per watt: divide each all-in system price by the system's size in watts (DC). In California in 2026, a fair owner-bought price is about $2.60–$3.50/W before incentives. Then compare the total 25-year cost — the sum of every payment. Do not compare on the monthly payment; it can be tuned to look small while hiding a higher total.
What is a hidden dealer fee on a solar loan?
It's a financing charge — in examples we’ve reviewed, sometimes 15–30% of the system price — that some solar lenders build in to offer a low or "0%" APR. The installer rolls it into your price, so the same panels cost more financed than in cash. To spot it, ask for the cash price and the financed price for the identical system; a large gap between them may reflect that fee — ask for a written breakdown.
Can I cancel a solar contract in California after signing?
Yes, if you signed at home. Under California's Home Solicitation Sales Act you can cancel in writing with no penalty. The cooling-off period is generally at least 3 business days — and 5 business days if you're 65 or older — though terms can vary by where and how you signed. The seller must return anything you paid within 10 days.
Why is one solar quote so much cheaper per month but not cheaper overall?
Usually because the loan is longer or a dealer fee is baked in. Stretching a loan from 15 to 25 years lowers the monthly payment while raising the total you pay. A "0% APR" can hide its cost in a higher system price. Add up the total across the full term — a lower monthly payment with a higher 25-year total is the more expensive deal.
What equipment details should be on every solar quote?
The exact panel brand, model, and wattage; the inverter type and brand (microinverters vs. string); estimated year-1 production in kWh; the product and performance warranties; and the installer's own workmanship/labor warranty (aim for 10+ years). If a quote just says "premium panels" with no make or model, treat that as a red flag.
Should I get more than two solar quotes?
Two is the minimum; three is better. Multiple quotes reveal the fair price per watt for your roof and reveal unexplained markups or financing fees. Use the cooling-off period and never sign under "today only" pressure — a legitimate installer's price is still good next week. Run every quote through the same 20-line checklist so you're comparing the same things.
Related reading
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Get a free estimatePrepared by Cali Energy, July 2026. This article is for general educational purposes only and is not legal, tax, financial, engineering, or utility advice. Rates, incentives, codes, permit requirements, equipment specifications, prices, and program terms may change; figures and timelines are estimates, not guarantees. Confirm current requirements with the applicable utility, AHJ, program administrator, manufacturer, or a licensed professional. See our Content Disclaimer. Cali Energy · 19201 Parthenia St Unit E, Northridge, CA 91324 · CSLB #1032379 (B, C-10, C-39)