Solar panel degradation rates: what to expect
All solar panels degrade over time — it's unavoidable physics. The question isn't whether your panels are degrading, but whether they're degrading faster than expected. Published research shows median degradation rates of 0.5–0.8% per year, but real-world rates vary significantly by climate, panel quality, and installation conditions.
Symptoms to watch for
Signs that this issue may be affecting your system
Natural panel degradation
CommonAll solar panels lose efficiency over time at roughly 0.5–0.8% per year. Accelerated in extreme heat or poorly manufactured panels.
What you can check yourself
Actions you can take today without professional help
Natural panel degradation
Compare current annual production to your system's first-year output. A decline beyond 1% per year may indicate accelerated degradation.
When to get a professional inspection
Signs you need professional help
Expected inspection costs
Drone thermal audit
Most comprehensive option
Handheld thermal scan
Best for smaller systems
Electrical inspection
Inverter and wiring only
Find inspection providers
Browse providers — US · UK · Australia · SpainIs your system affected?
Use our free Solar Loss Checker to get a personalised diagnosis with an action plan.
Based on conservative solar performance modelling and published degradation data
Updated June 2026 · Structured performance modelling
How we calculate →More guides
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Solar panel degradation rates: what to expect — By State
Frequently asked questions
How much performance loss is typical for this solar problem?+
Natural panel degradation typically causes 3–15% output loss on residential solar systems, depending on severity, panel count affected, and how long the defect has been present.
Can I detect this issue without a professional inspection?+
Some signs (visible discolouration, hot panels on a clear day, inverter error codes, year-on-year kWh drop > 8%) are observable from monitoring data. For confirmation, a thermal imaging inspection — drone or handheld FLIR — is the gold standard and costs $299–$549 for a residential system.
Is this covered under my panel or inverter warranty?+
Most tier-1 panel warranties cover defects causing performance below 80–85% of nameplate within 25 years, and inverter warranties run 10–12 years. Claims almost always require third-party diagnostic evidence (thermal images, IV-curve traces, or written performance reports).
How fast does this defect get worse if I ignore it?+
Untreated, natural panel degradation can compound — a single hot cell can degrade neighbouring cells through reverse bias, and a failing optimiser or inverter often cascades across strings. Typical degradation acceleration is 2–4× normal once a fault is present.
What does a thermal inspection cost to confirm this?+
A residential thermal solar inspection in the US costs $299–$549, UK £249–£449, and Australia AU$399–AU$699. Drone-based audits are usually at the lower end and complete a 10 kW array in under 20 minutes.
Should I repair, replace, or claim warranty?+
Rule of thumb: if defect-affected panels represent < 10% of array output, repair (e.g. bypass diode replacement, junction box rework). If 10–25% and within warranty period, file a claim. If > 25% and out of warranty, model the payback of partial re-power vs full replacement against current $/W pricing.