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Solar Warranty Comparison Calculator

Select your solar panels, inverter, and battery — get a coverage score, warranty timeline, gap analysis, and estimated replacement costs over 25 years.

Equipment selection
$
year
Warranty coverage analysis
Coverage score: 8/10
Panel product warranty25 years
Year-25 min output guarantee86%
Actual year-25 output (est.)86.5%
Inverter warranty expires2036 (12yr)
Battery warranty expires2034 (10yr)
Est. inverter replacement cost$2,000
Est. battery replacement cost$8,000
Total est. replacement costs$10,000
Coverage timeline
2024System installed — all warranties begin
2034Tesla Powerwall 2 warranty expires (replace ~$4,000-12,000)
2036SolarEdge HD-Wave (string) product warranty expires (replace ~$1,000-3,000)
2049Panel product warranty expires (25yr)
2049Panel performance guarantee ends — min 86% output guaranteed until this year
Coverage gaps
  • Inverter (SolarEdge HD-Wave (string)) warranty expires at year 12 — replace before system reaches full payback
  • Battery warranty expires at year 10 — plan for replacement cost
What is NOT covered
  • Labor costs after manufacturer warranty period (installer typically covers 10yr)
  • Physical damage from hail, wind, falling objects, fire
  • Damage from improper installation or unauthorized modifications
  • Cosmetic defects that do not affect performance
  • Damage from power surges or utility issues
  • Inverter replacement after product warranty expires (cost: $1,000-3,500)
  • Battery replacement after warranty expires (cost: $4,000-12,000)
  • Pest/rodent damage to wiring
Recommendation: Consider a third-party extended warranty from Sunnova, SunPower Care, or your installer for labor coverage beyond year 10.
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How to Use This Calculator

Select your equipment combination

Choose your panel manufacturer, inverter brand and type, and battery brand from the dropdown menus. Each option shows its warranty length alongside the product name — the key numbers to compare. The panel dropdown shows both product warranty years and the year-25 minimum output percentage, which tells you how much power is guaranteed 25 years after installation.

Enter system cost and installation year

Your total installed system cost helps contextualize replacement costs as a percentage of original investment. The installation year sets the calendar years for warranty expiry — so you can see at a glance when to budget for inverter or battery replacement. If you haven't installed yet, use the current year as a planning baseline.

Read the warranty analysis

The calculator shows a coverage score (1-10), a year-by-year timeline of key warranty events, coverage gaps, what is NOT covered by any warranty, and estimated replacement costs. The score penalizes short inverter warranties (the most common gap) and rewards premium panel performance guarantees and battery longevity warranties.

Key Warranty Terms Explained

Product Warranty: Covers manufacturing defects and premature failure Performance Guarantee: Guarantees minimum % of original rated output at year 25 Year-25 Output = 100% - (Annual Degradation Rate × 25 years) Coverage Score = Panel years (40% weight) + Performance % (20%) + Inverter years (30%) + Battery years (10%)

The performance guarantee is the most misunderstood part of solar warranties. A "25-year warranty" with 84.8% minimum output means your panels can legally produce only 84.8% of rated power at year 25 and still be within warranty. SunPower's 92% guarantee is significantly better — your panels will produce more power over the system's life even if the wattage is the same on day one.

Example

Rachel — Comparing premium vs. budget builds

Rachel is choosing between a SunPower + Enphase premium system ($28,000) and a Canadian Solar + Growatt budget system ($14,000). She wants to compare 25-year warranty coverage before deciding.

Premium: panelsSunPower — 40yr product, 92% yr25
Premium: inverterEnphase IQ8 — 25yr
Budget: panelsCanadian Solar — 25yr product, 84.8% yr25
Budget: inverterGrowatt — 10yr (replace ~2034)

Result

Premium coverage score9/10 — no major gaps
Budget coverage score5/10 — inverter replacement needed
Premium year-25 output93.75% of rated
Budget year-25 output86.25% of rated
Budget est. replacement costs~$2,000 inverter over 25 years

The budget system needs an inverter replacement around year 10, adding ~$2,000 to total cost of ownership. The premium system has no expected replacements within 25 years. When Rachel factors in the 7.5% more power the SunPower panels will deliver over 25 years and zero replacement costs, the $14,000 price gap narrows considerably on a 25-year basis.

FAQ

A product warranty covers manufacturing defects, premature failure, and physical problems with the panel itself — if a panel stops working or shows delamination, cracking, or cell failures, the manufacturer replaces it. A performance guarantee is different — it promises the panel will produce at least a specified percentage of its rated output throughout the warranty period. If your panel falls below that threshold due to degradation beyond the guaranteed rate, the manufacturer compensates you. Most manufacturers guarantee 80-92% of rated output at year 25.
String inverters contain electrolytic capacitors that degrade over time — their lifespan is typically 10-15 years in residential environments. Manufacturers offer 10-year warranties to reflect realistic component life. Extended warranties (10+10 or 25-year) are available from some brands for an additional cost at purchase. Microinverters (Enphase, APsystems) use fewer electrolytic capacitors and operate at lower temperatures per unit, enabling genuine 25-year warranties. When comparing bids, always ask if the inverter warranty is included or an upgrade.
This is a real risk — several solar panel manufacturers have gone bankrupt, leaving warranty claims unfulfilled. Mitigation strategies: (1) Choose manufacturers with strong financial backing and long US market presence (Enphase, SunPower, Canadian Solar, QCells). (2) Verify the manufacturer maintains a US subsidiary or distributor that can honor claims. (3) Ask your installer if they offer their own workmanship warranty backed by insurance. (4) Some states require installers to carry surety bonds. A third-party extended warranty from a financially stable insurance company (not the manufacturer) provides independent protection.
For product warranty claims: (1) Document the defect with photos and your monitoring system data. (2) Contact your installer first — many handle warranty claims as part of their service. (3) If your installer is unresponsive, contact the manufacturer directly with your purchase documentation. For performance claims: you need professional irradiance measurement data proving actual output is below the guaranteed threshold — this requires an independent solar assessment, typically $200-500. Most performance claims are complex to prove without professional documentation, which is why the product warranty is more commonly used.
Not exactly. A warranty is a legal promise to repair or replace defective equipment — it has defined terms, exclusions, and claims processes. A guarantee in solar usually refers to a production or performance commitment. The actual coverage depends on the fine print: does it cover labor? Does it require registered monitoring? Are there exclusions for weather events? Read the specific warranty documents for your equipment — not just the marketing headline numbers. Premium manufacturers (SunPower, Enphase) have notably fewer exclusions and faster claims processes than budget manufacturers.

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25-year return on investment including replacement cost scenarios.
⏰ Solar Payback Calculator
Calculate payback period accounting for degradation and rate changes.

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