Chapter 8 · Payback and ROI
8.7 Cash vs Loan vs PPA — three payment paths compared
| Payment method | Upfront | Monthly payment | 25-year total | Net benefit (vs no solar) |
|---|---|---|---|---|
| Cash | $30k | $0 | $30k | +$60k–$120k |
| Solar loan, 7% / 15-year | $0 | $270 | $48k | +$40k–$100k |
| PPA / Lease | $0 | $200 starting, with annual escalator | $84k | -$15k to +$30k (much worse) |
No cash but still want to go solar? Prefer a Credit Union HELOC or personal loan — the rate is usually 1–2 percentage points lower than the "solar-specific loan" products. Avoid solar loans laden with dealer fees.
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8.6 State-by-state payback (cash purchase, 2026 pricing)
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8.8 Mindset: treat solar as a financial product
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Questions after reading this section? Send us your utility bill — we will come back within one business day with a recommendation specific to your situation.