How long do solar panels last?
Updated August 2026
Solar panels last 25 to 30 years, and even at the 25-year mark a quality panel still delivers 80 to 90 percent of its original output. They rarely fail outright; they fade, shedding roughly 0.5 percent of their production each year, which is why most carry a 25-year performance warranty promising around 80 to 85 percent at the end. The glass-and-silicon panels are the durable part. The inverter is the weak link and usually needs replacing once during the array's life. One caveat before you install: a worn roof should be replaced first, because pulling panels to reroof later adds cost. A system runs $15,000–25,000 before incentives like the 30 percent federal tax credit.
Lifespan by type and situation
| Type or situation | Typical lifespan | Why |
|---|---|---|
| Monocrystalline panels | 25–35 years | The common choice; low 0.3–0.5% yearly degradation |
| Polycrystalline panels | 25–30 years | Slightly faster fade, still decades of service |
| Thin-film panels | 10–20 years | Cheaper and degrade faster; less common on homes |
| String inverter | 10–15 years | The part you will most likely replace mid-life |
| Microinverters / optimizers | 20–25 years | One per panel, warrantied around 25 years |
| Mounting and racking | 25–30+ years | Aluminum and stainless outlast the panels if flashed right |
| Output at year 25 | 80–90% | Panels fade, they rarely just stop |
Signs yours is near the end
- A steady year-over-year drop in production beyond the usual half-percent slide
- Visible cracking, delamination, or cloudy "snail trail" lines across the cells
- Brown or yellowed patches where the laminate has broken down
- A monitoring app flagging one panel or string producing far below the rest
- Corrosion at the junction boxes or connectors
- The inverter throwing repeated faults or going dark, often the first real failure
How to add years
Solar is close to set-and-forget, but a few habits protect the payback. Rain handles most cleaning, yet in dusty, pollen-heavy, or wildfire-smoke regions a yearly panel cleaning recovers output that grime quietly steals; letting that buildup sit can cost 5 to 20 percent of production. Watch the monitoring app so a failing panel or inverter is caught in weeks, not years, and walk the solar panel checklist each spring for corrosion and loose mounts. When production sags for good, the choice is usually inverter-only, so weigh repair versus replacement before touching the panels themselves.
What it costs to replace: plan on $15,000–25,000 before incentives (a single inverter swap is $1,500–3,000). Replacing on your own schedule, before it fails, is almost always cheaper than the emergency version. The home maintenance cost calculator helps you set the money aside before it comes due.
OnOtto tracks your solar production checks age and service history, and warns you before end of life instead of after the flood.
Track your home's systems, free for 30 daysFrequently asked questions
Do solar panels stop working after 25 years?
No. Twenty-five years is the warranty period, not an expiration date. Most panels keep generating well past it, just at a lower level, typically 80 to 90 percent of new at year 25 and continuing to slide by about half a percent a year after that. Plenty of 1990s-era arrays are still feeding power today. You replace panels when the output no longer justifies the roof space, or when a reroof forces the issue, not because a timer runs out at 25 years.
What part of a solar system fails first?
The inverter, almost always. A traditional string inverter lasts 10 to 15 years, roughly half the life of the panels, so expect to replace it at least once, usually for $1,500–3,000. Microinverters and power optimizers, one mounted under each panel, last 20 to 25 years and carry matching warranties, which is part of why they cost more upfront. Panels themselves rarely fail early; when production drops sharply, the inverter is the first suspect, not the glass on the roof.
Do solar panels need to be cleaned?
In most climates, not much. Rain rinses off the majority of dust and pollen, and the panels' tilt helps them shed debris. Where cleaning pays off is dry, dusty, or high-pollen regions, near agriculture, or after wildfire smoke and bird droppings, where buildup can shave 5 to 20 percent off output. A once-a-year rinse with a soft brush and plain water is plenty; skip harsh chemicals and pressure washers. A gentle, gradual production dip during a dry spell is the usual signal it is time.
Should I replace my roof before going solar?
If the roof is more than about 10 to 15 years into its life, replace it first. Panels last 25 to 30 years and are bolted down for the duration, so mounting them on shingles with only a decade left means paying to remove and reset the array when the roof gives out, often $1,500–6,000 in extra labor. Match the timelines instead: put a fresh roof under a new array and both reach the end together. A quick roof inspection before install settles it.