Solar financing options compared (2026)
| Financing type | APR range | Dealer fee? | Tax deductible? |
|---|---|---|---|
| HELOC | 7.10%-8.50% | No | Yes (as substantial improvement) |
| Home equity loan (fixed) | 7.90%-8.75% | No | Yes (as substantial improvement) |
| Cash | 0% | N/A | N/A |
| Solar dealer loan (Sunlight, Goodleap, LightReach) | 8.99%-14.99% | Yes (10-25% baked in) | Same rules as HELOC |
| Solar lease / PPA | N/A (lease, not loan) | N/A | No (you don't own the system) |
| PACE financing (property-assessed) | 6.75%-9.5% but 15-25 yr | Fees vary | Yes (paid via property tax) |
The dealer-fee reality
Solar dealer loans commonly advertise "0.99% APR" or "0.00% APR" promotions. Those are almost always subsidized by a dealer fee added to the loan amount. Common example:
- Cash price for a solar system: $30,000
- Financed price via 0.99% APR loan: $37,500 ($7,500 dealer fee baked in)
- Effective APR when you compute the true cost vs the cash system: ~9-13%
Solar contractors don't always show you the cash price and financed price side by side. Always ask: "What's the cash price of this system if I pay from a HELOC or savings, versus the financed price?"
Federal solar tax credit (30%)
Under the Residential Clean Energy Credit (IRC §25D), extended by the Inflation Reduction Act of 2022 and confirmed under the 2025 OBBBA:
- 30% of qualified solar costs is a federal tax credit (dollar-for-dollar reduction of your federal tax liability)
- No cap on the credit amount — a $50K system generates a $15K credit
- Non-refundable but carries forward — if the credit exceeds your tax liability in the installation year, remainder rolls to future years
- Method of financing doesn't matter — cash, HELOC, dealer loan, all qualify
Practical impact on a $30K system:
- Gross cost: $30,000
- Federal tax credit: -$9,000
- Net cost after credit: $21,000
Some states add additional rebates and credits. Check your state's Database of State Incentives for Renewables & Efficiency (DSIREUSA.org).
ROI math on a $30K solar system with HELOC financing
- System cost: $30,000
- Federal credit (30%): -$9,000
- Net investment: $21,000
- Financed via HELOC at 7.43% APR, 10-year term
- Total interest cost: ~$8,700 (varies with paydown pattern)
- Assumed monthly electricity savings: $150 (median US residential solar output)
- 10-year savings: $18,000
- Net 10-year benefit: $18,000 savings − $8,700 interest = ~$9,300 positive
- Plus system continues generating for 15-20 more years
If interest is tax-deductible (which for solar is typically true), effective interest cost drops further and net benefit increases.
Tax deductibility mechanics for HELOC-funded solar
Under TCJA (permanent under OBBBA 2025), HELOC interest is deductible when proceeds are used to "buy, build, or substantially improve" the home securing the loan. Solar installation on your primary residence:
- Constitutes improvement of the home ✓
- Adds to your home's tax basis for future capital gains calculation ✓
- Substantiation: keep the contractor invoice, permit, and utility interconnection documentation
Aggregate deduction cap: interest on up to $750K MFJ combined acquisition + qualifying home-equity debt. For most solar-only HELOC use, well under the cap.
Solar lease/PPA — usually the worst option
Solar leases and Power Purchase Agreements (PPAs) let you install solar without paying anything upfront. Sounds attractive; typically expensive.
- You don't own the system → don't qualify for the 30% federal tax credit
- Contracts typically 20-25 years — locks you into paying a third party
- Selling the home requires either buying out the lease or transferring to new owner (which frequently kills real estate transactions)
- Total system cost paid over 20 years is usually 1.5-2x what you'd pay via HELOC
Only reasonable scenario for a lease: you can't qualify for any financing AND you can't afford to install solar in cash.
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