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How Long Do Solar Panels Last?

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By This Old House Reviews Team Reviewed By Sarah Wilder 9/14/2023

Solar panels can last decades when well-maintained, but like any home appliance, they degrade over time. Most solar panels come with a warranty of 25–30 years, though it’s possible for them to continue working for longer. Our guide explains the factors that impact solar panels’ life span and provides tips for helping them last longer.

What Is the Life Span of Solar Panels?

High-quality solar panels can theoretically last up to 50 years, but most manufacturers warranty them for 25–30 years. That doesn’t mean your panels will stop working once they hit the 25-year mark, but they will drop in efficiency and energy production. Solar panel efficiency indicates how effectively your panels convert the sunlight it absorbs into energy. Over time, that efficiency declines and affects your energy production. This gradual decline in performance is called the degradation rate.

What Is Solar Panel Degradation Rate?

The solar panel degradation rate measures how much your solar panelspower output diminishes over time. A study conducted by the National Renewable Energy Laboratory (NREL) found that solar panels have an average degradation rate of 0.5% per year. So if your solar panels have been operational for five years, your power generation will be 2.5% lower than your initial output. If we apply this to 20-year-old panels, production drops to 90% of the original output

Some solar panel manufacturers include a power guarantee or warranty to back their panels’ output. This means your panels are guaranteed to perform at the rate outlined in your contract, or the manufacturer will replace or upgrade them. These policies vary among solar providers but may guarantee power production up to 90% or higher. For example, SunPower includes a power production guarantee of 92% after 25 years.

Which Solar Panels Have the Longest Life Span?

Your solar panels’ quality has a big impact on how long they last. Bloomberg New Energy Finance Corporation (BNEF) developed a tiered rating system to grade solar panel quality. Panels are divided into Tier One, Tier Two, and Tier Three. Tier One panels are produced by manufacturers with at least five years of experience, stable finances, and a solid brand reputation within the solar industry. These panels offer the highest power production, efficiency, and return on investment. They’re also the most expensive panel options. BNEF does not provide detailed criteria for Tier Two and Tier Three panels.

Among these Tier One solar panels, monocrystalline (mono) and polycrystalline (poly) are the most popular types of solar panels for home installations. Monocrystalline panels offer the best efficiency and power production, and they typically have a lower degradation rate. Poly panels are more affordable than mono panels, but they have a lower efficiency rating, which means the impact of the degradation rate will be higher.

Factors That Affect Solar Panel Life Expectancy

We’ve detailed several factors that can impact not just your panels’ longevity, but your whole system’s efficiency.

Your Climate

Though solar panels work best in sunny conditions, prolonged exposure to extreme heat reduces their efficiency. Frequent exposure to extreme weather, such as hail, high temperatures, and high winds, may also degrade your panels faster.

Panel Installation

Solar panels must be installed correctly in a racking system to keep them in place. A poor installation could cause the panels to slip, crack, or fall from the mounting system. Working with a reputable solar installer is essential to ensure your panels will last as long as possible. Some installers offer workmanship warranties that cover issues due to faulty installation. If any problems arise, they repair or replace your panels and fix any faulty mounting systems. 

Panel Quality

Investing in high-quality solar panels improves your system’s performance and protects against severe degradation. While all solar panels lose efficiency over time, high-quality panels have a lower degradation rate because they’re designed and built better. They use better solar cell technology, more durable materials, and improved designs to generate the best power output

Manufacturers typically include better warranty coverage with these types of panels. The industry standard is 12–15 years for the manufacturer’s warranty, which protects your system’s individual components in case of defects. Production warranties, or power production guarantees, are almost never less than 20 years. We recommend looking for companies that offer 25-year warranties to ensure your panels are covered throughout their lifetime.

How Can I Make Solar Panels Last Longer?

Though you can’t prevent panel degradation completely, you can take preventive steps to slow the process. We’ll share a few tips for keeping your panels in the best condition. 

Invest in Reliable Solar Equipment and Installers

Going solar can be expensive, and many homeowners choose cheap solar panels to save money when installing a system. The trade-off is lower power production, which impacts your total energy savings. We recommend investing in high-quality panels; they’ll be more expensive up-front, but they’ll last longer and produce more savings over time.

We also recommend taking advantage of solar incentives to reduce your solar panel installation costs. These incentives, such as the federal tax credit, provide tax breaks and rebates to make going solar more affordable. Incentives are offered at the federal and state levels and through local cities, municipalities, and utility companies. This is an excellent way invest in better equipment without overspending. 

Along with reliable equipment, you’ll need to find a trusted company to handle your installation. Look for experienced solar companies and installers with positive reviews and a solid reputation. Each solar company will have varying solar panel and battery storage options. We recommend comparing several companies and considering their reputation, experience, product selection, and customer reviews. 

Keep Your Panels Clean

Solar panels require little to low daily maintenance. The natural rainfall keeps the panels’ surface clean most of the time. However, heavier debris, such as snow or broken tree branches, can sometimes accumulate. This debris will block your panels’ ability to absorb sunlight, so it’s important to clear it off. Many solar panel installers include cleaning in comprehensive warranty coverage or as a separate service.

Perform Routine Maintenance and Servicing

Regular maintenance checks will help keep your solar panels working efficiently. Note that your solar panels aren’t the only component of your solar system. Solar panel systems include numerous parts that keep your system running, such as solar batteries and inverters. These individual parts will also have warranty coverage, but it varies among manufacturers. 

Many solar installers include regular system checks as part of their warranty coverage. In addition, some solar companies provide smart apps that track your system’s performance, health, and energy production.

When Should I Replace Solar Panels?

In most cases, solar panels continue to function even as they degrade in efficiency. However, they’ll eventually reach a point when they can’t produce enough power to sustain your home or provide energy savings. 

If you notice a significant drop in energy production or big changes to your electricity bill, it may be time to replace your solar panels.  You may also receive alerts about your panel’s health through your solar provider’s dedicated app. An alert could be a sign of panel damage or an issue with the system itself. We recommend reaching out to your solar installer to have your panels tested and possibly replaced if this occurs.

If your solar panels fail while still under warranty, your installer will repair or replace them. However, if panel failure occurs outside your warranty period, you’ll be financially responsible for the replacement. 

Our Conclusion

Investing in solar panels offers many long-term benefits. Though all panels degrade over time, you can extend their life span with routine maintenance and care. You should also consider investing in high-quality solar panels from a reputable company. Taking these steps should ensure your panels last 25 years or longer.

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FAQs About Solar Panels

What is the average life span of solar panels?

The average life span of solar panels is 25 to 30 years.

What is the payback period for solar panels?

The average payback period for solar panels is between six and 10 years.

Do solar panels become less efficient over time?

Yes, all solar panels lose their efficiency over time. High-quality solar panels typically degrade at a lower rate than cheaper, less efficient models. Loss of efficiency can be accelerated by other factors, including panel damage, extreme weather conditions, and faulty parts or installations. 

What happens to solar panels after 25 years?

After 25 years, solar panels will be less efficient and produce less power. This doesn’t mean your solar panels will stop working, but they may be less effective at powering your home and lower your energy savings. When panels degrade to the point where they no longer produce power, they’re ready to be recycled.

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