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How we research

Our methodology, in plain English.

How we source data, what we verify, what we don’t assume — and how to push back if you find something wrong.

Every claim on this site has a paper trail. We’re writing for homeowners about real money decisions, so “trust us” isn’t enough. Here’s how every page is built, and what you can do if something looks off.

01 / Primary sources

Where the numbers come from

APRs, term lengths, dealer fee ranges, and credit thresholds come from lender disclosure forms, official press releases, and NMLS Consumer Access (NMLS ID 1818140 for Sunlight Financial Holdings, Inc.). We do not estimate or interpolate. If a lender has not publicly disclosed a number, we either omit it or label it as a range.

For the federal Investment Tax Credit, we reference IRS Form 5695 instructions and the Inflation Reduction Act of 2022. Schedule and step-down dates come directly from the U.S. Department of Energy.

02 / Lifetime-cost math

How we run the numbers

All loan payment, total interest, and total cost figures are computed with the standard amortizing-loan formula:

M = P · r · (1+r)n ÷ ((1+r)n − 1)

where M is the monthly payment, P is principal, r is the monthly APR, and n is the term in months. For re-amortizing solar loans, we apply the rate-reset assumption from each lender’s product sheet rather than averaging.

Anyone can reproduce our numbers in the public calculator.

03 / Lender comparisons

How comparisons are scored

Lender comparisons (e.g., Sunlight vs. GoodLeap) are normalized to a representative borrower: 700 FICO, 25-year term, $30,000 system price, average dealer-fee tier. We disclose the assumption set at the top of each comparison so readers can see when their situation diverges.

Editorial ratings (1–5) are not aggregated from user reviews. They reflect our weighted scoring across cost transparency, rate competitiveness, term flexibility, customer-service track record, and product breadth. The weight scheme is published on the editorial standards page.

04 / Update cadence

When pages get re-checked

Every analysis and rates page is reviewed on a fixed cadence — at minimum every six months, more often if the lender announces a product or rate change. Each page shows the last-reviewed date in the byline. Major restructurings, acquisitions, or product launches trigger same-week updates.

This page itself was last updated in June 2026.

05 / What we don’t do

Conflicts and lines we hold

  • We don’t accept payment for favorable reviews. Lenders cannot pay to be included in comparisons.
  • We don’t reproduce sales-funnel copy from lenders or installers. Where promotional language is unavoidable, we mark it clearly.
  • We don’t use undisclosed AI-generated personas as authors. See the editorial standards page for how we use AI tools.
  • We don’t make personal financial recommendations. Everything here is general editorial guidance.
06 / Found something wrong?

Corrections policy

If a number on this site is wrong — a wrong APR, an outdated product tier, a competitor we mis-described — please email us at [email protected]. We aim to verify and publish a correction (with a dated note on the affected page) within 5 business days.

Material corrections that change a rating or recommendation will trigger a re-rating with the dated note preserved indefinitely.

Want the receipts?

Start with the Sunlight Financial.

Every claim links back to a primary source or the calculator.

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