How Reliable are Solar Panels and how long is a Solar System Warranty

How long do Solar Panels last and what is the Solar Panel Warranty and Guarantee

Solar panels are generally quite reliable. Remarkably, some Solar PV systems exceed 50 years in operation, though with a decreased efficiency compared to their initial installation. The physical structure of the panels is incredibly strong and they can endure most types of weather, particularly anything the inclement UK weather can throw at it. As long as the installation has been completed to a high standard, your panels shouldn’t provide you with any issues.

Solar panels can last longer than their product and performance warranty, surviving many different UK seasons.

Solar panels with 25 year product warranty

Assessing performance reliability, any reputable panel manufacturers, particularly those offering tier 1 products, should provide a robust solar performance warranty for 25 years. These warranties guarantee a panel's generation performance, typically pledging that after 10 years, the output won't drop below 90% of its initial generation, and within 25 years, it will remain above 85%. This is pretty impressive, therefore you seldom hear that solar panels have been replaced because of underperformance. Additionally, tier 1 panels typically come with a 10-year product warranty, covering non-performance-related issues. In reality, the manufacturers provide the guarantees on performance, knowing that their panels will comfortably achieve it, however this doesn’t mean that it will never happen.

Comparing Solar Panel, Inverter and Battery Warranty Durations

Warranty durations for batteries and inverters are shorter than those for solar panel performance warranties. Inverters and batteries are similar in that a lot come with a standard 5 year warranty, that can be extended to ten years. Some manufacturers offer this as a free warranty extension after registering your product, and for others there is a charge. There is a set time period from the date of installation that you need to register your system to obtain the extended warranty. It may be worth speaking with your installer to see if the extended warranty can be set up from the point of installation, meaning you might not need to worry about it.

Maintaining System Performance

To maintain your system's annual energy generation and therefore maintain performance reliability, routine maintenance is recommended and cleaning of the panels as it is needed (you can find detailed information in our article Does a Solar PV System Need to be Cleaned here). Some performance warranties and product warranties may require that some form of maintenance regime is followed, so it will be worth checking the small print on this and speak to your installer if you have any questions.

Installation Quality and Long-term Reliability

A properly fitted system—ensuring adequate rafter fixation to withstand wind loads, secure connections, and careful installation to minimise microcracks—tends to operate smoothly once generating energy. Notably, if the initial year or two passes without issues (which is often the case), the likelihood of future panel problems diminishes. Any subsequent faults within the system's lifetime are more likely to stem from other components, such as gradual loose connections.

Mechanical Durability of Solar Systems

Unlike commonplace issues in appliances like washing machines, where rotors or moving parts break, solar panels, inverters, and batteries experience fewer mechanical failures. There are no moving parts in solar panels which helps, and typically, inverters might incorporate just a cooling fan (or in some cases, none at all) to maintain efficiency, as excessive heat can affect performance. While certain manufacturers claim "quiet" and fanless inverters, their efficiency remains somewhat uncertain beyond manufacturer claims.