System specifications (1–6)
1. System size in kW DC — listed clearly (e.g., "8.4 kW DC"). This drives every other number.
2. Panel make, model, and wattage — exact model number, not just brand. Cross-check the spec sheet.
3. Number of panels — system size ÷ panel wattage. Should match.
4. Inverter make, model, and type — string inverter, microinverters, or DC optimizers. See our inverter comparison.
5. Mounting and racking system — IronRidge, Unirac, SnapNrack, etc.
6. Battery (if included) — make, model, usable kWh, warranty.
Production and savings (7–11)
7. Year-1 production estimate in kWh — the actual number, not a percentage.
8. Annual degradation assumption — typically 0.4–0.7% per year. Compare to panel warranty.
9. Shading analysis included — TSRF or solar access percentage per panel.
10. Production guarantee — does the installer guarantee year-1 production? What's the remedy if you fall short?
11. Utility rate escalation assumption — savings projections often assume 3–5% utility increases. Anything over 4% is aggressive.
Pricing (12–16)
12. Total cash price — before any incentives or financing.
13. Price per watt ($/W) — total price ÷ system size in watts. Compare to averages in our $/W guide.
14. Federal tax credit (cash/loan purchases only) — for systems placed in service in 2026 and beyond, this should be $0. The Residential Clean Energy Credit expired December 31, 2025. If a proposal still claims a 30% federal credit on a homeowner-owned system, the math is wrong.
15. State and utility rebates — listed by source and dollar amount. State and local incentives still apply.
16. Net cost after incentives — what you actually pay out of pocket.
Financing (17–20)
17. Loan APR and term — actual interest rate, not "promotional" rate. Watch for dealer fees.
18. Total interest paid over loan term — request the amortization schedule.
19. Re-amortization clause — many older solar loans assumed a tax credit paydown in month 18. With the credit gone, this can create payment shock. Make sure your loan doesn't have a re-amortization trigger that no longer makes sense.
20. Lease/PPA escalator (if applicable) — should ideally be 0%. Anything over 2% is risky.
Warranties and contract (21–25)
21. Panel product warranty — typically 12–25 years.
22. Panel performance warranty — typically 25 years at 80–87% of rated output.
23. Inverter warranty — 12 years standard, 25 years for premium microinverters.
24. Workmanship/installation warranty — 10 years minimum, 25 years from top installers.
25. Roof penetration warranty — separate from workmanship; covers leaks at mounting points.
Run all 25 checks automatically
Upload your solar proposal and our analyzer scores it across all 25 points — production sanity, pricing comparison, warranty review, and contract terms.
Analyze My Solar Bid →Frequently asked questions
How many solar bids should I get?
At least three. Compare equipment, $/W, warranties, and reputation — not just price.
What's a fair turnaround for a revised proposal?
2–5 business days. Anything longer suggests the installer isn't prioritizing your project.
Should I sign during the first visit?
No. Take 7–14 days to compare bids and read the contract carefully.
Can I negotiate solar pricing?
Yes. Most installers have 5–15% margin to negotiate, especially if you have a competing bid in writing.