Solar panels degrade 0.25–0.50% per year and need almost zero maintenance. After 25 years, your system still produces 87–94% of its original output. Here is what to monitor and when to file a warranty claim.
Degradation Rate
0.25–0.50%/yr
premium vs standard
Cleaning Frequency
1–2× per year
depending on climate
Product Warranty
12–25 years
manufacturing defects
Performance Warranty
25–30 years
80–92% guaranteed
Solar Panels Are Low-Maintenance — But Not Zero-Maintenance
One of the biggest solar myths is that panels require no maintenance. The truth: solar panels are low-maintenance, not zero-maintenance. With proper care, your panels will hit their 25-year production warranty. Neglect them, and you could lose 5–15% of your expected production — costing you thousands in lost savings.
This guide covers everything you need to know about maintenance tasks, degradation rates, how to read your monitoring data to spot problems early, and the step-by-step process for filing warranty claims when something goes wrong.
Solar Panel Degradation: What to Expect
All solar panels slowly lose efficiency over time. Premium panels degrade about 0.25%/year; standard panels about 0.40–0.50%/year. This is built into all payback and savings calculations.
| Year | Premium (0.25%/yr) | Standard (0.50%/yr) | % of Original |
|---|---|---|---|
| 1 | 11,970 kWh | 11,940 kWh | 99.5% |
| 5 | 11,851 kWh | 11,703 kWh | 97.5% |
| 10 | 11,703 kWh | 11,413 kWh | 95.1% |
| 15 | 11,558 kWh | 11,131 kWh | 92.8% |
| 20 | 11,414 kWh | 10,855 kWh | 90.5% |
| 25 | 11,272 kWh | 10,587 kWh | 88.2% |
What Causes Degradation?
UV Exposure
Sunlight breaks down the encapsulant layer protecting the silicon cells. This is unavoidable — it's why all panels degrade.
Thermal Cycling
Daily heating and cooling causes microscopic cracks in the cells and solder joints. Hot climates with 30°C+ temperature swings accelerate this.
Humidity & Moisture
Water vapor penetrates the panel edges and causes corrosion. Coastal areas and high-humidity climates see faster degradation.
PID (Potential Induced Degradation)
High voltage stress causes power loss. Quality panels have PID-resistant coatings, but cheap panels suffer from this in the first 5 years.
Real-World Degradation Example: Phoenix, AZ
A homeowner in Phoenix, Arizona installed a 10 kW system with mid-tier panels (0.50%/yr degradation) in 2016. Initial production: 15,000 kWh/year. Year 5 (2021): Expected production: 14,625 kWh. Actual production: 14,100 kWh (3.5% below expected). Cause: Excessive soiling (dust accumulation) + above-average thermal degradation due to 45°C+ summer panel temperatures. Solution: Annual panel cleaning increased production by 4%. By year 6, production returned to expected levels. Lesson: Degradation is predictable, but environmental factors (soiling, heat) can make it worse. Regular cleaning and monitoring prevent permanent production loss.
Seasonal Maintenance Calendar
Solar panels need attention 2–4 times per year depending on your climate. Here's a month-by-month guide to what you should check and when.
Spring (March–May)
- Visual inspection for winter damage: Look for cracked panels, damaged wiring, or dislodged racking.
- Clear debris: Remove leaves, twigs, and pollen that accumulated over winter. Use a soft brush or leaf blower — never pressure wash.
- Check for animal nests: Birds, squirrels, and rodents nest under panels in spring. Install critter guards if recurring ($300–$800).
- Monitor production ramp-up: April–May should be your highest production months. If flat or declining compared to last year (after accounting for weather), investigate.
Summer (June–August)
- Peak production verification: System should produce 90–110% of estimate. If below 85%, you have a problem.
- Check for new tree growth: Trees grow fast in summer. Even a single branch shading 10% of one panel can reduce production by 30–50%.
- Inspect for hotspots: Use a thermal camera or infrared thermometer ($30 on Amazon) to check for panels running unusually hot.
- Clean if needed: If you live in a dusty area, summer dust accumulation can reduce production by 5–10%. Rinse panels with a hose (early morning or evening only).
Fall (September–November)
- Pre-winter cleaning: Clear all leaves and debris before winter. Wet leaves trap moisture and promote corrosion. A single layer of wet leaves reduces production by 15–25%.
- Inspect mounting hardware: Check that all bolts, clamps, and rails are tight. Thermal expansion/contraction over summer can loosen hardware.
- Gutter cleaning: Clean gutters to prevent ice dams in winter. Ice dams can push water under shingles and cause leaks near panel mounting points.
- Inverter inspection: Check your inverter for error codes or warning lights. Fall is a good time to schedule maintenance before winter when access is harder.
Winter (December–February)
- Snow strategy: Let it melt naturally. Panels are dark and warm up quickly. Most snow slides off within 24–48 hours. DO NOT use a snow rake, shovel, or broom.
- Monitor production during clear days: After snow melts, check that production resumes immediately. If panels are clear but production is low, you may have a wiring issue.
- Inspect for ice damming: Ice dams can form at the lower edge of panels. If you see water pooling or icicles, gently remove ice buildup with lukewarm water.
- Indoor monitoring only: Do NOT attempt roof access in winter. Check your monitoring app daily and note any anomalies for spring inspection.
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How to Read Your Monitoring Data to Spot Problems
Your solar monitoring app (Enphase, SolarEdge, Tesla, etc.) is your early warning system. Most homeowners only check it once a month — but weekly monitoring helps you catch problems before they cost you hundreds in lost production.
Key Metrics to Track Weekly
Daily production (kWh)
Compare to the same week last year. A 5–10% difference is normal (weather varies). A 20%+ drop indicates a problem.
Peak power (kW)
Your system should hit its rated capacity (e.g., 10 kW) during peak sun (12pm–2pm on clear days). If peak power is 15–20% below rated, you have shading, soiling, or a failing inverter/panel.
Per-panel production (microinverters only)
All panels should produce within 5–10% of each other on clear days. A panel producing 30%+ less than its neighbors is failing or heavily shaded.
Inverter efficiency
Check DC-to-AC conversion efficiency. It should be 95–98%. If efficiency drops below 92%, your inverter is failing.
Real Monitoring Alert Examples
Example 1: Single Panel Producing 50% Less
What you see: Panel 12 is producing 80W while all others produce 150–160W.
Likely cause: Shading (tree branch, chimney shadow), soiling (bird droppings), or microinverter failure.
Action: Visually inspect panel 12. If clean and unshaded, the microinverter is likely failing. File a warranty claim with your installer.
Example 2: Entire String Down (String Inverter)
What you see: Production drops from 10 kW to 5 kW overnight. Half your panels show zero output.
Likely cause: String inverter failure, tripped breaker, or severed DC wiring.
Action: Check the inverter display for error codes. Reset the breaker. If the issue persists, call your installer immediately — this is a workmanship or equipment warranty claim.
Example 3: Gradual 15% Decline Over 3 Months
What you see: Production was 1,000 kWh/month in March, 950 in April, 900 in May — despite similar weather patterns.
Likely cause: Soiling (dust, pollen, pollution), tree growth creating new shade, or early PID (Potential Induced Degradation).
Action: Clean panels. Trim trees. If production doesn't recover, request a professional inspection — PID is a warranty-covered defect.
Understanding Solar Warranties
| Warranty Type | Covers | Typical Duration | Filed With |
|---|---|---|---|
| Product Warranty | Manufacturing defects, materials | 12–25 years | Panel/inverter manufacturer |
| Performance Warranty | Minimum production level | 25–30 years (80–92%) | Panel manufacturer |
| Workmanship Warranty | Installation quality, leaks, wiring | 10–25 years | Your installer |
Product Warranty
12–25 Years
Covers manufacturing defects: cracked cells, frame corrosion, junction box failure, delamination (bubbling), discoloration. This is your "the panel is broken" warranty.
Premium panels (REC, SunPower): 25 years
Mid-tier (Q Cells, Canadian Solar): 15–25 years
Value (JinkoSolar, Trina): 12–15 years
Performance Warranty
25–30 Years
Guarantees minimum production. Most warranties guarantee 92% of rated power in year 1, then 80–85% at year 25. If your panels degrade faster, the manufacturer replaces them.
Typical terms: 97% after year 1, then 0.5–0.7%/year degradation. At year 25, panels must produce at least 80–85% of original capacity.
Catch: Proving panels are underperforming is difficult without detailed monitoring.
Workmanship Warranty
10–25 Years
Covers installation quality: roof leaks, loose racking, wiring issues, inverter mounting, and system failures caused by poor installation.
Top installers: 25 years (NuWatt offers 25-year workmanship warranty)
Average installers: 10 years
Cheap installers: 5 years or less — this is a red flag
Step-by-Step: How to File a Warranty Claim
Filing a solar warranty claim is more complicated than most people expect. Here's the exact process so you know what to expect.
Document the Problem
Export 12 months of production data from your monitoring app (CSV or PDF). Take photos of the affected panel(s) or inverter from multiple angles. Note the date you first observed the issue. Record the panel serial number (usually printed on the back rail or junction box) or inverter serial number.
Contact Your Installer First
Always contact your installer before going directly to the manufacturer. The installer can often diagnose and fix the problem faster — and they may cover the cost under their workmanship warranty even if it's technically a manufacturer issue. Email or call with your documentation (photos, monitoring data, serial numbers). Request a site visit if the problem isn't obvious from monitoring data.
File a Manufacturer Warranty Claim
If your installer can't fix the issue or the problem is clearly a manufacturing defect, file a claim with the panel or inverter manufacturer. Find the warranty portal on the manufacturer's website (e.g., qcells.com/warranty, enphase.com/support). Submit required documents: Proof of purchase (invoice from installer), photos, monitoring data, serial numbers, installation date. Wait for review — manufacturers typically respond within 7–14 business days.
Approval and Replacement
If approved: The manufacturer ships a replacement panel/inverter to your installer (or to you if your installer is no longer in business). Installation cost: Manufacturer warranties cover the part only — not labor. Expect to pay $200–$500 per panel for removal/replacement labor. Some installers cover this under their workmanship warranty for the first 10 years. Timeline: From claim filing to replacement installation: 4–8 weeks typically.
If Your Claim Is Denied
Manufacturers deny claims for several reasons: improper installation, owner neglect, damage from external causes (hail, falling branches), or inability to prove the defect. Request a detailed denial reason. Appeal if appropriate — gather additional evidence and resubmit. Hire a solar engineer to inspect and provide a report ($500–$1,000). Escalate to workmanship warranty: If the manufacturer blames installation, file a claim with your installer.
When to File a Warranty Claim
- • Production drops more than 10% compared to same month last year (after accounting for weather)
- • Visible damage to panels (cracks, discoloration, hotspots)
- • Inverter error messages or offline panels in monitoring
- • Roof leak at mounting point (workmanship claim)
NuWatt Offers Industry-Leading Warranties
25-year production guarantee, 10-year workmanship warranty, and lifetime monitoring.