If a solar salesperson offers you a 25-year solar loan at 2.99% or 3.99% APR when U.S. Treasury bonds and prime mortgages are trading between 6.2% and 7.5%, ask yourself a simple question: How can a solar bank lend money for 25 years below the U.S. government's cost of borrowing?
The answer is delineated in the Consumer Financial Protection Bureau (CFPB) Issue Spotlight on Solar Financing: they don't. Instead, specialized solar lenders—led by GoodLeap, Mosaic, Sunlight Financial, and Dividend Finance—charge an upfront 22% to 35% "Dealer Fee" (points buydown) and silently embed it into the "System Purchase Price" on your contract.
You can calculate the exact dollar fee hidden in your proposal right now using our interactive Solar Loan Dealer Fee Unmasker.
1. How the Dealer Fee Math Works Behind the Scenes
When a solar sales rep opens their lender portal (GoodLeap or Mosaic) on an iPad, they see a rate sheet that looks like this for a $24,000 cash system:
| Loan Product Selected by Sales Rep | Lender Dealer Fee (%) | Dollar Fee Added on Day 1 | Total Loan Principal Signed by Homeowner | True Effective APR |
|---|---|---|---|---|
| Same-As-Cash / 9.99% APR (Par Rate) | 0% – 3% | $0 – $720 | $24,000 | 9.99% APR |
| 25-Year @ 5.99% APR | ~18.5% | +$5,448 | $29,448 | ~8.7% APR |
| 25-Year @ 3.99% APR | ~28.0% | +$9,333 | $33,333 | ~8.9% APR |
| 25-Year @ 2.99% APR | ~33.5% | +$12,090 | $36,090 | ~9.2% APR |
Because the lender divides the cash price by (1 - Dealer Fee %), a 32% dealer fee marks up a $24,000 cash price by +47.0% ($11,294) on Day 1!
2. Why Truth in Lending Act (TILA) Disclosures Don't Warn You
Under the federal Truth in Lending Act (TILA), banks are required to disclose finance charges and prepaid points in the APR box on your loan truth-in-lending statement.
Why doesn't a $11,294 GoodLeap or Mosaic dealer fee show up as a finance charge on your TILA disclosure? Because the solar installer inflates the "Cash Price of the System" on the purchase agreement to $35,294 and prohibits the sales rep from showing you the $24,000 cash price! Both the CFPB and multiple State Attorneys General have targeted this exact practice as a deceptive hidden finance charge.
3. The 18-Month Re-Amortization Trap
Historically, solar lenders structured 25-year loans with a mandatory Month-18 balloon payment (often equal to 30% of the loan balance). Even though the homeowner 30% federal tax credit (§25D) was repealed for systems installed after December 31, 2025 (P.L. 119-21), many solar loan structures still advertise a "low teaser monthly payment" for the first 18 months that jumps by 38%–42% in Month 19 unless you make a massive lump-sum principal payment out of pocket.
4. Three Rules to Beat Solar Dealer Fees
- Demand the Unfinanced Cash Price First: Never tell a solar installer how you plan to pay until you have a written, itemized Cash Purchase Quote in hand. Compare that quote against state benchmarks in our Solar Quote Red Flag Checker.
- Never Buy Down a Solar APR if You Might Move or Refinance Within 10 Years: If you take a 0%-fee credit union loan at 7.5% APR and pay it off in Year 4, you pay zero future interest. If you take a 3.99% solar loan with a $11,000 dealer fee and pay it off in Year 4, you lose the entire $11,000 fee.
- Buy Tier-1 Hardware Directly: Purchasing an EG4 18kPV Hybrid Inverter + 14.3kWh WallMount Battery (
$8,200) or EcoFlow Delta Pro Ultra ($5,799) directly and paying a local master electrician $2,000 for installation eliminates both the $8,000 sales commission and the $11,000 lender dealer fee.