What Happens to Solar Panels After 25 Years?

The short answer: your solar panels keep working. A common misconception is that solar panels "expire" or stop functioning at the end of their 25-year warranty period. They don't. Solar panels are solid-state devices with no moving parts — they degrade slowly and continue generating electricity for 30, 35, or even 40+ years, just at gradually reduced output.

Research from the National Renewable Energy Laboratory (NREL) on real-world panel performance shows that the median solar panel degrades at approximately 0.5% per year. At that rate, a panel that produced 400W when new will produce about 340W in year 25 — still 85% of its original output.

Understanding Solar Panel Degradation

Degradation is the gradual reduction in a panel's power output over time, caused by UV exposure, thermal cycling, humidity, and physical stress. There are two main degradation patterns:

Light-Induced Degradation (LID)

In the first few hours to days of operation, solar panels experience an initial output drop of 1–3% called light-induced degradation. This happens when light exposure causes changes in boron-oxygen pairs within the silicon. After this initial dip, degradation slows significantly. This is why manufacturers often rate panels at their post-LID performance level.

Potential-Induced Degradation (PID)

PID occurs when high voltage stress causes ions to migrate through the panel's glass and encapsulant layers, reducing cell efficiency. Modern panels are designed with PID-resistant encapsulants and anti-reflective coatings, making PID much less common than it was in panels manufactured before 2015.

Degradation Rates by Panel Technology

Panel Technology / Brand	Annual Degradation Rate	Output at Year 25	Output at Year 30
SunPower Maxeon (back-contact)	0.2–0.25%/yr	94–95%	93–94%
REC Alpha HJT	0.25–0.3%/yr	92–94%	91–93%
Panasonic EverVolt HJT	0.26%/yr	93%	91.7%
Q CELLS PERC (standard)	0.45–0.55%/yr	86–88%	83–86%
Canadian Solar PERC	0.45–0.50%/yr	87–88%	84–86%
Industry Standard (NREL median)	0.50%/yr	87.5%	85%
Older panels (pre-2015)	0.8–1.0%/yr	80–82%	76–80%

What the 25-Year Warranty Actually Covers

Most solar panels come with two warranties:

• Product/materials warranty (10–25 years): Covers manufacturing defects, delamination, and physical failures. If a panel stops working due to a defect before this period expires, the manufacturer replaces it.
• Power output warranty (25 years): Guarantees the panel will produce at least a specified percentage of its rated output through year 25. Premium brands guarantee 92%; standard manufacturers typically guarantee 80–87%.

When the warranty expires, neither coverage applies — but the panel doesn't stop working. It simply continues to degrade at its natural rate beyond the warranty period.

Year-by-Year Output: A 8 kW System Over 30 Years

Here's what annual production looks like for an 8 kW system in Los Angeles, using a standard 0.5%/year degradation rate and a starting production of 13,000 kWh/year:

Year	Annual Production (kWh)	% of Original	Cumulative Savings (at $0.30/kWh)
Year 1	13,000	100%	$3,900
Year 5	12,740	98.0%	$19,332 cumulative
Year 10	12,415	95.5%	$38,077 cumulative
Year 15	12,100	93.1%	$56,382 cumulative
Year 20	11,795	90.7%	$74,253 cumulative
Year 25	11,500	88.5%	$91,698 cumulative
Year 30	11,213	86.3%	$108,725 cumulative

Note: Cumulative savings also grow due to electricity rate increases. Assumes a conservative 3%/year rate escalation.

Do Inverters Last as Long as Panels?

No — and this is the most important maintenance consideration for solar system owners. Inverters have a typical lifespan of 10–15 years for string inverters and 20–25 years for microinverters.

Most homeowners can expect to replace their inverter at least once during the system's 25-30 year life. A string inverter replacement costs approximately $1,500–$3,500 installed. Microinverter replacement (one unit per panel) costs $150–$300 per unit installed.

Battery storage systems (if added) have even shorter cycles: lithium-iron phosphate (LFP) batteries typically carry 10-year warranties and may need replacement in 12–15 years.

When Should You Consider Replacing Panels?

Replace your panels when:

• Physical damage (cracked glass, delamination, water intrusion) is reducing output below what normal degradation explains
• Panel technology has advanced so significantly that newer panels on the same roof footprint would produce meaningfully more power (e.g., replacing 15-year-old 300W panels with 450W panels)
• Roof replacement requires panel removal anyway — this is often a natural opportunity to upgrade

Don't replace functioning panels simply because the warranty has expired. A system producing 87% of original output in year 25 is still generating substantial value — particularly as electricity rates continue to rise.

What Happens to Old Solar Panels?

Panel recycling is an emerging industry. Most solar panels are made of aluminum frames, tempered glass, silver contacts, and silicon — all recoverable materials. Several companies now offer solar panel recycling programs, and several US states (including California and Washington) are developing or have passed extended producer responsibility legislation requiring manufacturers to fund end-of-life recycling programs. By the time panels installed in 2026 reach end-of-life in 2050, recycling infrastructure will be substantially more mature than it is today.