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How Long Do Solar Panels Last in the UK (2025)?
- Solar panels last about 25 to 30 years before significant efficiency degradation kicks in. They can continue to operate beyond this (30 to 35 years), albeit with lower energy generation.
- Solar panels with string inverters may need these components replaced after 10 to 25 years, while panels with microinverters will typically last around 25 years.
- Different solar panels have varying degradation rates, with an average amount being 0.5% per year after the first year.
- Life expectancy affects the efficiency and output of the panels, making them less effective at generating electricity over time.
How long does a solar panel last? This can vary depending on the brand, type of panel, and the rate of degradation. However, most solar panels last for about 20 to 30 years before they become unprofitable to run. While they can still operate, they will do so with less output. Solar panel efficiency decreases over time, affecting how well the solar panels produce electricity.
In this article, we’ll go over how long solar panels can last in more detail and what measures can help delay degradation.
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Solar panel lifespan in the UK
A solar panel’s lifespan is generally between 20 and 30 years, after which it degrades excessively. It can continue to function past this age but will have decreased energy efficiency and may not bring in the returns one would expect. Most warranties for solar panels are, therefore, set at about 20 to 25 years.
Luckily, 25 years can be a sufficient time to make more than enough of a return on investment, amounting to £11,000 - £12,000 for the average home with a 4kW system. After about 11 to 8, the average solar panel cost will be covered, and the solar panels can generate profits after the break-even point for another decade.
How do solar panels degrade?
In the first year, solar panels lose 2% to 3% due to a phenomenon called Light Induced Degradation. Panels will degrade at an annual rate of between 0.2% and 0.8% per year after the first year. This will decrease their efficiency and ability to convert solar energy into electricity.
The total life expectancy of solar panels is determined by the rate of degradation. The best solar panels in the UK tend to have a degradation rate between 0.2% and 0.4%. Solar panel systems with a low degradation rate include REC Alpha Pure-RXr (0.2%) and SunPower Maxeon 6 (0.25%).
Another aspect of solar panels that can degrade is the inverters, which convert DC electricity into AC. Inverters can be internal (microinverters within each panel) or external (string inverters). Microinverters tend to last approximately 25 years, while string inverters last between 12 and 25 years, depending on the quality of the parts.
There are 3 types of degradation that solar panels can experience across its lifespan:
- Infant defects: These defects are often attributed to poor design or manufacturing issues. Even with great quality control, there are some things that can not be prevented (such as Light Induced Degradation, which happens in the first year).
- Mid-life defects: Mid-life defects are random issues that can arise due to technology defects. Stronger PID (Potential-induced degradation), diode failure, cell interconnection breakage, and degradation in glass present some of the issues that you can run into. However, these are far less common once the panels are set up.
- Wear-out defects: Wear-out defects near the end of the PV module’s life when the power output falls below 70% to 80%. This can lead to the discolouration and delamination of PV cells. Wear-out defects ordinarily occur after the warranty period is over.
The following graph shows how defects can occur across the life of a solar panel:
As the graph illustrates, early defects happen early on but are less likely throughout the warranty period. At the end of the warranty period, the number of defects, including excess degradation, aesthetic flaws, and mechanical failures, can climb quickly.
What influences the life expectancy of solar panels?
- Type of solar panels: The most common type of solar panel is monocrystalline, but other types can vary in terms of degradation. Polycrystalline solar panels will degrade faster than monocrystalline panels, at a rate of 0.8% to 1% annually. Similarly, integrated solar panels start off with a lower level of efficiency due to their installation requirements. This can make any degradation more drastic over time.
- Solar panel quality: High-quality solar panels are less prone to excessive degradation. Brands like the SunPower Maxeon line have very low degradation rates (0.2%) but can be very expensive. Larger solar panel sizes and wattage can help decrease the amount of output lost.
- Installation quality: How well your panels are installed on your roof can also determine their life expectancy. Proper mounting and providing adequate ventilation can increase the life expectancy of your solar panels.
- Maintenance: Dust and other obstructions can decrease solar panel efficiency. Solar panel maintenance has little to no cost, but it can be important to avoid the build-up of various blockages and debris that damage the solar panels.
- Environmental factors: Extreme storms, hail, and high moisture environments can increase wear and tear for solar panels. Alternatively, milder climates can enhance their lifespans, while hot humid ones can increase failure rates.
How do you protect the lifespan of solar panels?
- Buy high-quality solar panels: Research the brand properly and read the manuals they provide to find out the specifications. You can also look up reviews and ask questions on solar community pages to get feedback from buyers. You should consider all the pros and cons of solar panels on the market.
- Ensure proper installation: The best way to ensure proper installation is to research your installer, look up reviews, and get multiple quotes to see what the best offer is.
- Maintain them regularly: Solar panels are fairly easy to maintain, as this can be done with household items like soft brushes and soap. Aside from that, it’s important to keep the panels free from falling branches. This should be done either every 6 months or when there is a significant dip in their performance.
- Inspect their output: There are apps and monitoring systems that can be a great way to keep an eye on your output and efficiency.
- Shelter against extreme weather: If you live in an area prone to heavy storms, protective covers can come in handy. These days, most solar panels have high tensile strength and are not easy to break, but regions with extreme weather may degrade them faster over years of operation.
When is the right time to replace solar panels?
Generally, you should replace solar panels after 30 years. With most solar panels, this is when the degradation will reach a point where it can become less profitable. Similarly, this will have been more than enough time to earn back enough money to buy new panels and even have a profit on top of that.
Of course, the time at which you have to replace solar panels will vary based on how much they degrade and whether they perform well relative to your home’s energy usage. This often means that better-quality solar panels will be more expensive.
Are solar panels worth it if they degrade quickly?
Such panels will most likely have to be replaced fairly quickly and may not have the best warranties. They will usually be cheaper, so if the price allows for a low break-even point and a decent return on investment, panels with low degradation can be worth it. However, those panels with a longer lifespan can be more profitable and offer better warranties.
That’s why it is important to have a reliable installer who provides you with the best options at a reasonable price. Finding one can be a huge hassle that requires hours of researching and compiling their prices to compare. That’s why our service is a great alternative.
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