How long do Solar Panels last in the UK?

Written-by

Janet Richardson

Reviewed-by

Richard Burdett-Gardiner

Updated on

Sep 29, 2024

How long do Solar Panels last in the UK?

Solar is becoming increasingly popular as a means for generating the energy our homes and lifestyles require. Solar panel (PV) systems will save you money on your energy bills and protect you from future price increase, they're also environmentally friendly as they do not produce any emissions. Another plus is that solar panels need minimal maintenance because the lack of moving parts makes them very unlikely to break down.

The warranty periods for solar panel systems tend to be quite long as well, due to the average solar panel's life expectancy, which we will cover further on in this article.

This article not only details how long solar panels last, but also shows how you can keep them from deteriorating.

Solar Panel Lifespan

Due to rising energy bills and a growing desire to reduce our carbon emissions and impact on the environment, solar panels are becoming an increasingly popular format for the provision of energy to homes in the UK. The latest solar panel models on the market can have a lifespan as long as between 40-50 years, and warranties that will keep them protected for at least half of that time. However, it is important to remember that solar panels slowly degrade over time and will produce less electricity. Solar panels are generally expected to last for 25 to 30 years. 

The warranties also act to guarantee the performance levels of the solar panels over the course of the first half of their lives. Most warranties will guarantee that the performance will not drop below 80% before the warranty ends. In fact, some panels have been known to remain over 80% efficient even past the end of their lives. If you take good care of your solar panels, then they could easily last over 40 years after being installed. However, it is essential to remember that their performance levels will have deteriorated slightly over that time period.

The life expectancy of around half a century applies to both monocrystalline and polycrystalline solar panels. The reason thin film is not included is because we don’t yet know how long their estimated lifespan is, and this is why their warranties also tend to be shorter. Please note that the size and wattage of a system should never impact its lifespan.

The Causes of Degradation

Before installing solar panels, you should consider their degradation rate and what factors affect their lifespan. To ensure your solar panels operate for the length of time promised by their manufacturers you will need to conduct regular checks and maintenance. By doing this you can monitor the efficiency of your solar panels to ensure they are still adequately providing energy for your home. 

Even though the quality of solar panels and their installation play an important role in guaranteeing an estimated lifespan of 25 years or more, your solar panels inevitably become less efficient over time. 

The degradation rate of solar panels is calculated as a percentage. Experts estimate that most solar panels degrade at a rate of around 0.2% – 0.5% per year. This means that the output of usable energy generated by your solar panels slowly decreases over time. 

How does Solar Panel Degradation Work?

Degradation can be age-related, light-induced, potential-induced, related to thermal cycling, caused by damp heat or humidity freeze, or due to UV exposure. 

Here’s an explanation of each:

Age-related degradation: 
Some wear and tear to your solar panels is to be expected. Being exposed to various weather conditions such as humidity, strong winds, and high temperatures will cause some damage to your solar panels.
These factors can lead to frame corrosion, cause the crystalline silicon to harden, or lead to cell contamination. Adverse weather conditions can also damage the surface of the panel and prevent adequate sunlight absorption. 

Light-induced degradation (LID): 
This type of degradation happens when the solar panels are first exposed to sunlight. Traces of oxygen in the silicon wafer lead to a power stabilisation phase that causes a degradation rate of about 0.25% to 0.7% per year. 

Potential-induced degradation (PID): 
When solar panels are exposed to both high voltage and high temperatures potential induced degradation occurs. This can cause a loss of up to 30% when it comes to generating energy. 

Thermal cycling: 
When there is a fluctuation in temperatures it causes the contraction and expansion of solar panels which is referred to as thermal cycling. Thermal cycling can cause microcracks to appear which will reduce the efficiency of your panels in the energy production process. 

Damp heat: 
High temperatures and high humidity levels can lead to the corrosion of your solar panels. 

Humidity freeze: 
If solar panels are exposed to high humidity and then rapidly cooled by low temperatures, cracks can appear on the surface of solar panels. 

UV exposure: 
UV radiation can cause the degradation of your solar panels due to the encapsulation material deteriorating.

Crystalline silicon modules that are located in extreme climates have shown higher degradation rates than those in moderate ones. For very cold climates, panels that were subjected to heavy snow and wind tended to suffer the most. Similarly, panels that were installed in a façade in the same climate showed very low rates of degradation as the snow load was eliminated.

On the other side of the climate spectrum, solar panels in desert climates displayed large decreases in production over time (close to 1% per year) due to the high levels of UV exposure. This decrease is massive compared to moderate climates, which tend to be around 0.2% per year. Panels in moderate climates tend to be able to retain 96% of their production capabilities after 20 years.

What is a Solar Inverter and How Often do they Need to be Replaced?

Solar inverters are electrical converters, a component of your solar panel system that changes the direct current (DC) electricity captured by your solar panels, into alternating current (AC). AC is the standard flow of electricity required to power your home appliances and connect to the National Grid. 
Solar inverters work by doing the following: 

• DC electricity being channelled through a transformer 
• The transformer lowers the voltage and changes to AC.
• The DC runs through two or more transistors.
• These are rapidly turned on and off to feed the two different sides of the transformer.

The size of the solar PV system you require will determine the type of inverter that is best for your system. Prices can vary greatly but a new string inverter for a typical residential home would cost approximately £500-£1,000. The type of solar inverter you choose will affect the overall cost of your solar panel system installation.

The cost and installation of the solar inverter should be included in the initial quote from your solar panel installer. As mentioned before the solar inverter is unlikely to last as long as your solar panels which have an impressive lifespan. This means that your solar inverter will need to be replaced at some point.

The savings that you can expect from using a specific type of solar inverter will depend on the size of your system, the amount of energy it produces, and how much electricity your household uses. It’s recommended that you talk to a qualified installer about this in more detail as they will be able to advise you on the option that suits you best.  Generally, the more a solar inverter costs, the greater the efficiency levels will be. However, it’s worth bearing in mind that even the lower-cost models can achieve a conversion rate of around 93%. 

There are three main types of solar inverters, string inverters, microinverters, and power optimisers. Here’s a brief description of each: 

String inverters
String inverters use a proven technology that has been around for decades. Solar panels are arranged into groups or rows, with each panel installed on a ‘string’. Multiple strings can be connected to a single inverter, which transforms the DC electricity produced by the panels into appliance-friendly AC electricity.

However, there is a downside to string inverters. If the performance of one panel is reduced, for example by damage or shading, the performance of the whole solar array can be affected. 

Microinverters
Often a popular choice for residential solar systems, these inverters are fitted to each individual solar panel and convert DC to AC on the roof removing the need for a separate inverter. 

Because of the way the conversion works, if one or more panels are in the shade it won’t impact the performance of the rest of the solar panels. It’s also possible to monitor how well each individual solar panel is working. 

Microinverters are often considered a good solution to installing more solar panels on your roof as panels that may be in partial shade for part of the day won’t affect the performance of the other panels that remain in the sunlight. 

Although microinverters are still a relatively new technology and are generally more expensive than other inverter types, the additional cost may be offset by an increase in energy production. 

Power optimisers
These inverters are also located on each individual panel and offer many of the benefits of microinverters as well as being slightly less expensive. They work differently from microinverters as they don’t convert DC to AC at roof level but instead move the DC to a string inverter. You should also be able to monitor the performance of each panel via an online portal. 

How long will your solar inverter last?

Because your solar inverter is constantly working to convert the electricity current it will most likely need to be replaced approximately every 10 to 15 years. This will cost you around £800 depending on the system size and the manufacturer.  Some inverters have useful online monitoring functions and can warn you by email if the system fails.

Most inverters have warranties of five years as a minimum which you can often extend up to 15 years. It’s advisable to speak to your installer about the likely lifespan and benefits of an extended warranty. You should give careful consideration to extending your warranty as it may end up costing as much as a replacement inverter.

How to Maintain your Solar Panels and Extend their Lifespan

If you keep your solar panels well maintained, then you can expect to enjoy them for the full length of their estimated lifespan. There are a few ways in which you can do this, helping the efficiency levels to stay at their best. While solar panels should be pretty much self-sufficient after installation, an annual (or biannual) clean can really help them stay maintained.

It is important to note that you only need to give your solar panels a good clean once or twice a year, but if you have had a long period with no rain, you may want to give them an extra once over.

Here are some quick cleaning tips:

• Clean your solar panels in the morning or evening as they can get very hot during the day
• You should always start by gently sweeping leaves and debris from the surface of the panel. Make sure you used a soft bristled brush
• Check that there are no sharp objects around your solar panels like rocks or other materials that could potentially damage them
• Spray the panels with your garden hose, but use a gentle stream
• If the panels need a few stubborn areas cleaned further, wipe them down with warm water and a soft cloth to avoid scratching. You can use mild soap and water (or vinegar) if necessary

Safety precautions when cleaning:

• You should always refer to the manufacturer's guide before you use any cleaning products on the panels
• Always take precautions when reaching the panels, as they tend to be quite high. If in doubt, there are professional panel cleaners that you can call
• Only ever clean the surface of the panels, never touch the wiring underneath. You can use a solar panel cleaning service for under the panels, as they are trained and qualified

Ensure that your solar panels are working as efficiently as possible:

Get a Regular Inspection of the Panels

Regular inspections will ensure that your system is running as efficiently as possible
It can give you peace of mind knowing there aren’t any problems as well as extend the life of your solar panels
An annual repair or maintenance check can help prevent a small problem from turning into a bigger one which could also be expensive
Repairs should only be carried out by professionals

Protect your panels in extreme weather conditions

• It is vital to avoid any damage to your panels
• It can be worth covering your solar panels with a tarpaulin during any big storms or harsh weather conditions to shelter them from rain, sleet, hail, and snow
• Keep an eye on weather forecasts so that you take preventative measures if necessary
• Solar cells are designed for use in specific temperature ranges so protecting the surface of your solar panels in extreme temperature fluctuations will increase their efficiency and extend their lifespan.
• If action is required, it will ensure that your panels will continue to produce energy efficiently by protecting them from damage

Seal gaps around the edges of your solar panels with sealant products

• Physical damage can shorten the life of your solar panels so it is important to make sure there are no gaps in the panels because it can let in different materials such as dust and insects that can damage or lead to less efficiency and overall reduce the lifespan of your system. 

Apply a quality protective coating every few years

• Applying a protective coating to your solar panels can not only maintain their appearance but also extend their durability
• UV lights contain too much energy and can damage the surface materials of your system, leading to lower efficiency and a shorter lifespan
• The metal parts of your solar panels can also become corroded which will also reduce their longevity
• The protective coating forms a physical barrier between the elements and the solar panels extending their life for a longer period

The other thing you can do to keep your solar panels maintained is ensure that there is nothing hanging over them, like tree branches. The shade produced by them will greatly reduce the overall efficiency of your panels, but they could also damage the panels if they fall on them. Any cracks on the surface of your solar panel could also prove very dangerous as water is able to seep into them freely. This could lead to the disintegration of the contacts, resulting in poor connectivity.

However, solar panels do have built-in safeguards to ensure that the damage made to one panel will not spread to others.

Want to Know More?

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