How Long Do Solar Panels Last?
Most residential solar panels carry 25- to 30-year performance warranties, and many keep producing electricity beyond that period. But “how long they last” has two different answers: what the warranty promises, and how long the hardware physically keeps working. Actual service life and output depend on the module, the installation and your site — and the panels usually aren’t the first thing to need attention.
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- Panels typically carry 25–30 year performance warranties; many operate beyond that.
- Product/materials and performance warranties are separate — and the installer’s workmanship warranty is separate again.
- Output declines slowly — an illustrative ~0.5%/year (NREL median; the mean is higher).
- Inverters and other electronics are more likely than the modules to need service over the array’s life.
Two warranties, two promises
When a manufacturer says a panel “lasts 25 years,” they’re usually talking about a warranty — and there are two kinds. Don’t conflate them:
Product or materials warranty
Covers manufacturing defects and failures in the module itself. Its length varies by manufacturer and can differ from the performance-warranty term, so read it separately.
Performance warranty
Guarantees the panel will still produce at least a stated percentage of its original output after a set number of years (commonly 25–30). It’s about output over time, not defects.
Separately, your installer typically provides a workmanship warranty that covers the installation work — mounting, wiring and labor — and is distinct from the panel manufacturer’s product and performance warranties.
Reference: DOE — Solar Performance and Efficiency. Exact terms vary by manufacturer — read the actual warranty documents.
How much do panels degrade?
Solar panels lose a small amount of output each year, a process called degradation. NREL’s long-running review of field studies found a median around 0.5–0.6% per year, with a mean closer to 0.8–0.9% — so a well-made modern panel commonly retains the large majority of its output after 25 years. The exact rate depends on the module and the conditions it lives in. The tool below shows what that gentle decline looks like — as an illustration, not a prediction for any specific panel.
See how gentle degradation really is
Panels don’t stop at year 25 — they slowly produce a little less each year. Move the slider to see an illustrative curve at about 0.5% per year. This is a scenario, not a prediction for any specific panel.
Illustrative degradation curve
A visual of how slowly output declines — not a forecast or warranty tool.
Fixed at an illustrative 0.5% per year (NREL reports a median near 0.5–0.6%, with a higher mean). Your panels’ actual rate depends on the module and site.
Usually not the panels
Over a solar system’s life, the inverter and other electronic components are more likely than the modules to require service. Panels are simple, solid-state and weather-rated; inverters do continuous electrical work and are the more common service item. When you budget for the long haul, plan around the electronics — not the glass. See how long home batteries last for the storage side.
What makes panels last (or not)
Build quality
Better materials, encapsulation and manufacturing lower the degradation rate and the odds of early defects.
Installation
Proper mounting, wiring and ventilation protect the modules and the electronics behind them — workmanship matters.
Site & climate
Conditions vary across the LA region. Inland roof temperatures, equipment ventilation, soiling and installation quality can all affect long-term system performance.
Maintenance
Occasional cleaning and keeping an eye on inverter health help the system hold its output over decades.
So how long, really?
A reasonable way to think about it: the performance warranty (25–30 years) is the promise you can hold the manufacturer to, and many panels keep generating usefully beyond that — just at gradually reduced output. There’s no single expiry date; there’s a slow decline plus the reality that other components may be serviced first. If a proposal quotes a flat “lifespan” number, ask what it’s based on and what the actual warranty documents say.
Sources & methodology
Primary sources: NREL — Photovoltaic Degradation Rates (Jordan & Kurtz) · DOE — Solar Performance and Efficiency · NREL — PV Field Performance and Reliability. Degradation ranges are from NREL’s review of field studies (reported median around 0.5–0.6% per year, mean closer to 0.8–0.9%). The tool shows an illustrative degradation curve, not a prediction of any specific panel or a warranty calculation. Warranty terms vary by manufacturer — read the actual product and performance warranties.
Frequently asked
How long do solar panels last?
Most residential panels carry 25- to 30-year performance warranties, and many continue producing electricity beyond that period at gradually reduced output. There’s no single “expiry” date — the panels degrade slowly, and actual service life depends on the module, the installation and your site conditions.
What's the difference between a product warranty and a performance warranty?
A product (materials) warranty covers manufacturing defects and failures in the module itself, and its length varies by manufacturer. A performance warranty guarantees the panel still produces at least a stated percentage of its original output after a set number of years (commonly 25–30). They’re separate promises, so read both — and note that your installer’s workmanship warranty, covering the installation labor, is separate again.
How much do solar panels degrade each year?
NREL’s review of field studies reports a median degradation around 0.5–0.6% per year, with a mean closer to 0.8–0.9%. That means a good modern panel commonly retains the large majority of its original output after 25 years. The exact rate depends on the module and conditions, so treat any single figure as illustrative.
What part of a solar system fails first?
Usually not the panels. Over a system’s life, the inverter and other electronic components are more likely than the modules to require service. Panels are solid-state and weather-rated; inverters do continuous electrical work. Budget for the electronics rather than assuming the glass is the weak point.
Do solar panels still work after the warranty ends?
Typically yes. The performance warranty (25–30 years) is a guarantee, not a shut-off. Many panels keep generating usefully past that term, just at somewhat lower output as degradation accumulates. Whether it’s worth keeping older panels depends on how much output has dropped and the condition of the rest of the system.
Related reading
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Get a free estimatePrepared by Cali Energy, August 2026. This article is for general educational purposes only and is not legal, tax, financial, engineering, or utility advice. Rates, incentives, codes, permit requirements, equipment specifications, prices, and program terms may change; figures and timelines are estimates, not guarantees. Confirm current requirements with the applicable utility, AHJ, program administrator, manufacturer, or a licensed professional. See our Content Disclaimer. Cali Energy · 19201 Parthenia St Unit E, Northridge, CA 91324 · CSLB #1032379 (B, C-10, C-39)