How long do solar panels last?

• Solar panel performance degrades by 1% to 2% in the first year and 0.25% to 0.55% per year afterward.

• Factors like build quality, environmental conditions, and maintenance can affect solar panel lifespan.

• You can get the most out of your panels by choosing high-quality panels and cleaning them regularly.

Home solar panels provide energy directly from the sun and require minimal maintenance. While they don’t last forever, most panels deliver guaranteed production for at least 25 years, which is the baseline many people mean when they ask, “how long do solar panels last?” With normal wear and basic upkeep, many systems keep generating electricity well beyond that point. In this article, we’ll explain average solar panel lifespan, expected output over time, and what shortens or extends service life.

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How long do solar panels last?

Modern solar panels typically deliver 25 to 30 years of guaranteed power output under a performance warranty. When people search how long do solar panels last, they’re usually asking how long the panels will keep producing enough electricity to justify the investment—and for most homeowners, that’s measured in decades.

All panels lose a small amount of performance each year, so after 25 years, output is commonly about 84% to 92% of the original factory rating, depending on the manufacturer’s degradation rate. Your solar panel warranty often covers 25 years of production, but many systems continue generating power well beyond the warranty period. You don’t “throw away” 25-year-old panels; you evaluate their remaining output and compare it to your household needs.

Monocrystalline panels are the most common type today, and with correct installation and basic solar panel maintenance, they can keep producing electricity for 30 to 40 years.

What are normal degradation rates?

Output degradation is one of the downsides of solar panels. Leading manufacturers usually guarantee 98% to 99% performance after the first year. Then, they guarantee performance won’t degrade by more than 0.25% to 0.55% per year. After 25 years, this means you’ve only lost about 8% to 16% of output performance.

Here are the main causes of performance degradation over time:

• UV exposure: Yes, even solar panels are damaged by the sun’s radiation over time. UV radiation can break down molecular bonds in the panels on a microscopic level.

• Temperature: Hot weather and wide temperature swings create thermal stress that wears on solar components.

• Microcracks: Moisture can enter older panels through microcracks and reduce system lifetime.

• Light-induced degradation (LID): Monocrystalline cells paradoxically lose some output shortly after installation when receiving the first rays of the sun. This is why panels can degrade 1% to 2% in the first year and then a fraction of a percent after that.

• Potential-induced degradation: Voltage differences between materials inside a solar panel can cause electrons to leak from the system.

Do solar panels make your roof last longer?

Solar panels can protect the roof directly underneath from UV rays, hail, and snow. Nature takes a toll on your roof over time, and solar panels can block its harmful effects. The small air gap acts as a layer of insulation, too. You might even find the room underneath your panels stays at a more constant temperature throughout the year.

That said, installing panels won’t fix issues with your roof. And if you have an old roof, it’s better to replace the roof before adding panels.

Factors that affect solar panel lifespan

The natural degradation from UV exposure, temperature fluctuations, and potential microcracks can all affect how long a solar panel system lasts. Mild climates tend to help panels last longer even though they don’t provide as much peak sun as hotter climates. We’ll cover some main factors here.

1. Degradation rate

Degradation rate directly determines how long solar panels last before output drops to a level you consider “too low.” A panel rated at 0.25% yearly degradation can deliver noticeably more total energy over 20–30 years than one rated at 0.55%, which can translate into meaningful differences in lifetime bill savings.

Because output declines over time, a newer solar system can support home value by promising decades of remaining production. If you’re selling a home with a 20- to 25-year-old system, buyers may ask how long the panels will last from that point forward and whether replacement will be needed soon—even if the panels still operate.

2. Build quality and materials

Manufacturers with the best build quality usually offer better longevity, and they may also offer better warranty terms.

Solar panel manufacturing is divided into three tiers. Tier 1 manufacturers account for 2% of the market and are financially sound enterprises that have been in business for many years. Tier 2 manufacturers are small to mid-sized companies that offer good value. 

Tier 3 manufacturers really don’t manufacture the solar cells, they assemble components from third parties. Lower-tier panels, while more budget-friendly, might degrade faster and have shorter warranty periods.

3. Environmental conditions

Local conditions can shorten solar panel lifespan through thermal stress, corrosion, and weather exposure, so how long solar panels last varies by region. Panels don’t age the same way everywhere.

Hot climates can produce strong solar generation, but high heat and rapid temperature swings can stress materials over many years. More temperate zones often provide steadier conditions that support long-term output. High winds, high humidity, heavy snowfall, and hail risk can also speed up wear or increase the chance of damage.

Coastal areas add another challenge: salt air can corrode mounting hardware and frames over time if components aren’t rated for that exposure or if fasteners and rails aren’t properly selected.

4. Maintenance

You have some control over your panel’s lifespan by practicing regular maintenance. The minimum recommendation is to clean your solar panels twice a year. However, if you don’t get much rain during the year, you might have to clean your panels more often to wipe away dust and debris, which can sap efficiency. You’ll also have to clean them more often if you have a flat roof.

Know your solar panel warranty

Manufacturers offer two types of warranties: performance and product. Performance warranties guarantee minimum solar panel output over a specified period of time like 25 years. Product warranties cover manufacturing defects in materials and workmanship. These usually last from 12 to 25 years.

Below are a few popular solar panel brands along with information on their warranties. These apply to the specific panel models below, and warranties can vary for different panels.

Improving solar panel lifespan

If you want a clear, practical answer to how long do solar panels last, focus on two things: buying durable equipment and preventing avoidable wear. Start with well-made panels, then maintain the system so it keeps producing at expected levels for decades.

Here are a few things to keep in mind:

• Choose the highest-quality panels you can afford, especially models with lower published degradation rates.

• Hire a reputable installer so the racking, flashing, wiring, and grounding are installed correctly and built to last.

• Clean your panels at least twice a year, and more often if dust, pollen, or bird droppings regularly collect on the array.

• Trim tree branches that could fall, scrape the glass, or drop debris that reduces output over time.

• Schedule an inspection every few years to check mounting hardware, wiring condition, and inverter performance.

• Consider add-on protection like mesh bird and critter guards to prevent nesting and wiring damage.

Owning solar panels is a long-term investment. Consider the pros and cons carefully because solar panels aren't best for everyone.

Wrapping up: Solar panel lifespan

While solar panel performance degrades at predictable rates, you can expect to get at least 25 to 30 years of high performance out of your system. With good maintenance, you can continue to power your home even after that point.

FAQ about solar panel longevity

Below are a few frequently asked questions about how long solar panels last:

What happens after 25 years of solar panels?

Solar panels still work after 25 years, just with 85% to 90% of their original output. You might keep using them, or you may want to replace them at that point.

How often do solar panels need to be replaced?

You shouldn’t have to think about replacing solar panels for about 30 years. However, if you add electric vehicles to your home or increase your usage, you might want to upgrade your system before then.

How efficient will solar panels be in 10 years?

Most solar panels from leading manufacturers will be 92% to 95% as efficient after 10 years compared to day one.

Do solar panels need maintenance?

Solar panels need minimal maintenance. This includes cleaning a couple of times a year and inspections every few years to make sure everything looks good.