Solar panel installation can represent a serious investment, so homeowners often want to know how long it’ll be before they’re looking at replacing anything.
Most solar panels are designed to last 25 to 30 years, and some keep producing electricity well beyond that. That’s a long time to spend on a California rooftop, though. There’s the summer heat, salty air along the coast, and the occasional stretch of smoky skies during wildfire season.
These factors can help determine how long your panels last and how efficiently they’ll produce electricity while in operation. We’ll explain more about solar panel lifespans and identify some of the key factors that’ll determine how long yours are likely to last below.
What’s the Average Lifespan of Solar Panels?
Most residential solar panels have an expected lifespan of up to 30 years, but that doesn’t mean they’ll suddenly stop working once they hit that age. Plenty of panels continue generating electricity for years afterward.
The bigger question is how much electricity they’ll still be producing.
Solar panels gradually lose some of their ability to convert sunlight into electricity as they age. This is called solar panel degradation, and it’s a normal part of owning a solar system. The decline is usually slow enough that you won’t really notice it from year to year.
Research from the National Renewable Energy Laboratory (NREL) puts typical annual solar panel degradation at roughly 0.5% to 1%. At a steady 0.5% annual decline, a panel could still produce about 88% of its original rated output at year 25.
Of course, actual performance depends on the panel, its installation, and the conditions it faces over time.
There’s also a difference between a panel’s lifespan and its warranty. Many manufacturers offer performance warranties lasting 25 years or longer, but those warranties generally guarantee a minimum level of output rather than promising the panels will never need repairs.
How Does California’s Climate Affect Solar Longevity?
California gets plenty of sunshine, which is great for generating solar power.
But spending decades exposed to the elements can take a toll on rooftop equipment. Most solar panels are built to handle outdoor conditions, but those same conditions can affect how quickly they age and how efficiently they work.
Heat and UV Exposure
Solar panels need sunlight to generate electricity, but high temperatures can actually make them less efficient. On a hot afternoon, the panels themselves can get considerably warmer than the surrounding air, causing electricity production to drop temporarily.
Years of heat and UV exposure can also contribute to the deterioration of certain panel materials, including protective encapsulants and electrical connections.
Coastal Salt Air and Moisture
Salty air is something else to think about when you live on the coast. Moisture and salt deposits contribute to corrosion, especially around exposed metal components, electrical connections, and mounting hardware.
Solar panels designed and installed for coastal conditions can withstand years of exposure, but the quality of the equipment and installation counts. Corrosion-resistant mounting materials and properly protected electrical connections can help reduce the risk of premature deterioration.
Wildfire Smoke and Ash
You don’t have to live particularly close to a wildfire for the smoke to affect your solar panels. Smoke can travel hundreds of miles, blocking some of the sunlight that would otherwise reach your roof.
The U.S. Department of Energy reports that wildfire smoke reduced solar power production by 10% to 30% across California during September 2020, with losses reaching 58% in some locations.
Smoke-related production losses usually aren’t permanent, but ash left on the panels can continue interfering with electricity generation until it’s removed. Nearby fires can also cause physical damage through extreme heat.
Heavy Rain and Winter Storms
Winter storms can put solar panel mounting systems to the test, especially when strong winds whistle in to accompany the rain. A properly installed system should be able to handle typical local weather, but severe storms can still cause damage.
After a particularly rough storm, check your system’s monitoring app for unusual production changes and look for visible damage from the ground. If anything seems off, have a professional inspect it before the problem gets worse.
What Are the Signs Your Solar Panels Are Nearing the End of Their Lifespan?
Solar panels rarely stop working overnight just because they’re getting up in age. In most cases, you’ll see a gradual decline in electricity production as the panels age. But there are a few signs your system might need some TLC, especially if it’s been on your roof for more than 20 years.
Keep an eye out for:
- Declining Electricity Production: A gradual decrease is normal, but a noticeable drop that can’t be explained by weather, shading, or seasonal changes might indicate a problem.
- Visible Damage: Cracked glass, discoloration, delamination, or corrosion can let you know the panels are deteriorating.
- Recurring System Errors: Frequent shutdowns or error messages may signal trouble with the inverter, wiring, or other electrical components.
- Higher Electricity Bills: If your utility bills are climbing despite similar electricity usage, your solar system might not be producing as much power as it used to.
Before assuming your panels need replacing, it’s worth having a professional do an inspection. A failing inverter or damaged electrical connection can cause production problems even when the panels themselves have years of useful life left.
How Can You Extend the Life of Your Solar Panels?
Solar panels don’t need much coddling, but that doesn’t mean you should forget about them once they’re installed. Here are a few ways to take care of your investment:
- Keep the Panels Clean: Dust, pollen, bird droppings, and coastal salt deposits can accumulate on the glass and block sunlight. Follow the manufacturer’s cleaning recommendations, and avoid abrasive tools or harsh chemicals.
- Monitor Electricity Production: Check your system’s monitoring app periodically. A sudden or unexplained drop in output could be an early sign that something needs attention.
- Schedule Regular Inspections: Have a qualified pro check the panels, mounting hardware, wiring, and electrical connections for signs of wear or damage.
- Address Problems Promptly: If you or your electrician finds a problem, have it fixed sooner rather than later. Things like a malfunctioning inverter or loose connection can affect system performance.
- Keep Nearby Trees Trimmed: Branches can shade panels, drop debris onto the roof, or cause physical damage during strong winds.
Safety First: Keep Your Feet on the Ground
You don’t need to — nor should you — climb onto your roof to keep your solar panels in good shape. Most day-to-day monitoring can be done from the ground, and cleaning or repairs that require roof access are best left to professionals.
When Should You Replace Your Solar Panels?
You don’t have to replace your solar panels just because they’ve reached the 25-year mark, but it might be a good idea to consider it if:
- Repairs are getting expensive. The cost of repairing damaged or failing panels is starting to outweigh what you’d spend replacing the affected equipment.
- Your electricity needs have changed. You’ve added an EV, switched to electric appliances, or otherwise increased your household’s power consumption.
- More efficient panels are available. Modern panels may generate more electricity in the same amount of space, especially if your existing system is several decades old.
- You’re planning major roof work. If your roof needs replacing, it may be a convenient time to evaluate an aging solar system before paying to remove and reinstall it.
A full solar replacement can cost thousands of dollars, so it’s worth having your system evaluated before making that investment. You may find that a targeted repair or equipment upgrade makes better financial sense.
Solar Panel Lifespans: Frequently Asked Questions
If you’ve still got a few questions about your solar system, we’ve got answers. Here are answers to a few of the ones we get most often.
Can solar panels last 40 years?
It’s possible, but their electricity production will probably be lower than when they were new. Most modern panels are designed for two to three decades of useful service, but, of course, that can vary based on equipment quality, installation, maintenance, and environmental conditions.
Do solar panels degrade faster in California’s heat?
High temperatures can accelerate certain types of solar panel degradation, particularly with prolonged exposure. The extent depends on the panel’s materials, design, and operating conditions.
Does coastal salt air damage solar panels?
It can, specifically by corroding solar panel frames, mounting hardware, and electrical connections. This is more common closer to the coast. Panels and mounting systems rated for coastal environments can help combat this problem.
How much efficiency do solar panels lose each year?
Solar panels usually lose around 0.5% of their output annually, though degradation rates can vary. At that rate, a panel could retain roughly 88% of its original output after 25 years. Check your manufacturer’s performance warranty for the degradation rate expected for your particular panels.
How often should solar panels be inspected in California?
It’s a good idea to have your solar panels inspected annually, or more if they start giving you trouble. Follow your installer’s and manufacturer’s recommendations for your specific equipment.
Is it worth replacing 20-year-old solar panels?
It can be, especially if their declining output no longer meets your electricity needs or newer equipment would be financially beneficial. If the panels are still working well, keeping them may be the better investment. If you’re on the fence, have a performance evaluation done — that can give you a better idea of potential costs and savings.
How much does it cost to replace solar panels in California?
New solar panels in California usually cost somewhere around $21,000, though that can vary quite a bit based on the equipment you choose, the size of your system, and the complexity of the installation. If you want a better idea of what it’d cost for your home, start with a custom estimate.
Keep Your Solar Panels Performing With Fisher Electric
If your solar panels are showing their age or aren’t producing as much electricity as they used to, we can help. Fisher Electric provides solar system troubleshooting, repairs, and upgrades for homeowners throughout San Jose, Santa Cruz, and surrounding communities.
Contact us today to schedule a solar system evaluation.
Sources & References
- Energy Solutions Intelligence – “Solar Panel Degradation Rates (July 2026 Update): Complete NREL Analysis & Financial Impact”
Reviews solar panel degradation rates, differences between panel technologies, and the effects of heat, humidity, and environmental exposure on long-term electricity production. Includes performance projections over 25 to 30 years.
https://energy-solutions.co/articles/sub/solar-panel-degradation-rates-2026 - EnergySage – “California Solar Panel Cost: 2026 Prices and Savings”
Provides California-specific solar installation pricing, including average costs, system-size comparisons, and estimated savings. Useful for contextualizing the financial considerations of installing a new solar system.
https://www.energysage.com/local-data/solar-panel-cost/ca - ScienceDirect – Research Article (Title Unverified)
The article’s title and abstract still need verification before adding a description of its findings.
https://www.sciencedirect.com/science/article/pii/S1876610213000829 - U.S. Department of Energy – “Solar Photovoltaic Hardening for Resilience – Wildfire”
Explains how wildfire smoke, ash, and extreme heat affect solar photovoltaic systems. Includes California research documenting electricity production losses during the September 2020 wildfires and discusses ways to reduce wildfire-related risks.
https://www.energy.gov/cmei/femp/solar-photovoltaic-hardening-resilience-wildfire
