Quote audit · operational checklist

Questions to ask before signing a solar contract.

Updated May 16, 2026. Sources verified the same day. We rerun this guide every quarter against the DOE, IRS, LBNL, and NREL reference pages.

The salesperson has been at the kitchen table for ninety minutes. The proposal is open to the signature page. Something feels off, but you've been steered through six pages of glossy production charts and a payback figure that arrived without parentheses. You know you should ask something. You just don't know what.

Twelve questions. Write them down before the meeting. Read them out loud. Insist on written answers — verbal answers do not survive into the contract. If the answer is “we'll add that later,” the answer is no.

Production and system spec (4 questions)

1. What is the first-year production estimate in kWh, and is it backed by a written guarantee? Production estimates should fall in the 1,000–1,600 kWh per kW range for typical US residential systems⁴. A proposal claiming 1,800+ kWh/kW for a roof that isn't in the Southwest desert is a number worth questioning. If there's no guarantee — or the guarantee is a soft “we estimate” rather than a hard kWh-floor with a remedy — the number is marketing, not a commitment.
2. What software produced the production estimate, and can I see the full output? A reputable installer uses NREL's PVWatts (free, public, auditable) or a commercial equivalent like HelioScope or Aurora. “Proprietary modeling” without a named tool is a hedge. Ask for the full simulation output — losses, shading factor, tilt, azimuth, soiling assumption — not just the headline number.
3. What annual degradation rate is built into the 25-year output? Most modern panels degrade ~0.5%/yr; older quotes sometimes assume 0.25–0.3% to inflate lifetime production. A 25-year output table claiming 95% Year-25 performance is built on numbers that don't match standard panel warranties (typically 84–87% at Year 25).
4. What happens if my production falls more than 10% short of the estimate in a given year? Some installers offer a true-up — they cut a check for the underproduction. Most do not. If the answer is “weather variability is the homeowner's risk,” understand that the production claim has no contractual weight. It's a sales chart.

Price and financing (4 questions)

5. What is the cash-only price for this exact system? Not the financed price. Not the “after tax credit” price. The dollar amount you would pay today if you wired cash. The gap between cash and financed totals is where dealer fees live — Berkeley Lab documents the range at 5–50% of the upfront price²for loan-financed residential systems. If the installer can't produce a cash-only number, walk. If the cash number is identical to the financed principal, ask twice — that would be unusual.
6. Is there a dealer fee built into the financed price? What is it paying for? Most teaser-rate solar loans (1.99%, 2.99%) are subsidized by a dealer fee paid to the lender at origination. Berkeley Lab documented financed prices including dealer fees of 5–50%². The fee is a real number on the lender's books; it should be a real number on yours.
7. What is the total amount I will pay over the life of the loan, including all fees? Term × monthly payment plus any origination, prepayment, or balloon fees. Compare that total to the cash-only price. The gap is the true cost of financing — and it's the number the APR doesn't show you, because the APR is computed against the inflated principal.
8. Is the loan secured against my home (lien), and what happens if I sell or refinance? Some solar loans place a UCC-1 fixture filing or formal lien on the property. Others are unsecured personal loans. Buyers and refi underwriters scrutinize both — and a lien you didn't expect can delay or kill a sale. Get the lien answer in writing before signing.

Tax credit and timing (2 questions)

9. When will my system be “placed in service” under the IRS definition, and is that date in the contract with a remedy if it slips? The IRS Form 5695 instructions³define “placed in service” as the completion of installation — not the contract date, not the deposit date, not the permit-pull date. The 2025 federal law ended the residential credit for systems placed in service after Dec. 31, 2025. A 2026 install does not qualify. If the installer commits to a completion date that lands in 2025 but slips into 2026, you lose 30% of eligible cost. Get the date in writing, with a remedy clause.
10. If the system is placed in service after Dec. 31, 2025, is the quoted price reduced to remove the tax-credit assumption? A common 2026 quote pattern: the proposal still bakes in a 30% credit calculation, even though the system won't qualify. The headline “net price after credit” is an illusion. Ask for a re-quote that removes the credit line. If the installer refuses, the proposal was never an honest price.

Workmanship and recourse (2 questions)

11. Is the lead installer NABCEP-certified, and who actually shows up on install day? The DOE Homeowner's Guide¹recommends NABCEP-certified installers and flags “Talk to certified installers” as one of four consumer-protection priorities. Many quotes come from sales-only franchises that subcontract installation to a different crew. Ask for the company name of the actual installer, their license number, and their record with your state contractor board.
12. What is the workmanship warranty, who honors it if you go out of business, and what's the cancellation window on this contract? A 10-year workmanship warranty is the consumer-friendly default; a 1-year warranty is a tell. The DOE¹ also points readers to FTC, CFPB, and state-utility complaint channels when an installer disappears. Most state contractor laws give a 3-day cancellation window after signature; some go longer. Get both numbers in writing.

What to say if the salesperson declines to put it in writing

Calmly, without raising your voice: “I understand. If it's not in writing, it's not part of the agreement, so I'm not going to sign tonight. I'm happy to revisit once the answers are documented.” Then put the pen down. A salesperson who can't document their claims is not the salesperson you want enforcing them in three years when something goes wrong. The reputable installers will email a revised proposal the next morning. The rest will tell you the pricing “expired,” which is itself a red flag worth walking out on¹.

These twelve questions are the operational version of the audit. The full quote-reading guide explains the five numbers on the proposal that decide whether the math holds up. The red-flags guide catalogs the pitches that should make you walk before the questions even start. And the quote calculator runs the math against public data, line by line.

1. 1. U.S. Department of Energy, "Homeowner's Guide to Going Solar." Lists four consumer-protection red flags: "Don't give in to pushy sales tactics," "Talk to certified installers," "Understand your financing options," and "Report bad actors." Recommends NABCEP-certified installers and points readers to FTC, CFPB, and state-utility complaint channels. Verified 2026-05-16. energy.gov/eere/solar/homeowners-guide-going-solar ↩
2. 2. Berkeley Lab, "Tracking the Sun, 2024 Edition" (Executive Summary, August 2024; data through year-end 2023; sample ~3.7M U.S. distributed PV systems). State-level median residential installed price in 2023: $3.20–5.20/W. Loan dealer-fee gap, verbatim: "a large portion of residential systems are loan-financed, and installed prices reported for these systems likely include dealer fees, adding anywhere from 5-50% to the total up-front price paid by the customer." Verified 2026-05-16. emp.lbl.gov · Tracking the Sun 2024 (PDF) ↩
3. 3. IRS Form 5695 (2025) instructions, verbatim: "You can't claim residential clean energy credits for expenditures made after December 31, 2025." The One Big Beautiful Bill Act, signed July 4, 2025, terminated §25D for systems placed in service after that date. Verified 2026-05-16. irs.gov/instructions/i5695 ↩
4. 4. NREL PVWatts (v8) — annual production estimator using NSRDB irradiance data with default 14% total system losses (soiling, shading, snow, mismatch, wiring, connections, light-induced degradation, nameplate rating, age, availability). Typical US residential output: 1,000–1,600 kWh/kW annually. Verified 2026-05-16. pvwatts.nrel.gov · API docs ↩

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