Solar panel maintenance: explained

Solar panels are long-lasting, low maintenance and generally robust, meaning that once you’ve installed your solar panels you’re unlikely to have significant problems down the line. 

However, there are still things that can go wrong – pieces of equipment fail, debris can hit a solar panel, and occasionally we get heavy snow falls. But even if none of those things happen, a little bit of effort can keep your panels working better, for longer. 

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Do solar panels need maintenance?

Generally speaking, solar panels are very low maintenance – there are no moving parts, so there isn’t much that needs checking. 

As long as there isn’t anything stopping the sunlight getting to the panels – such as leaves, or debris left behind by heavy snow, for example – everything should work. 

The other good news is that regular rain will clean your panels for you. 

A general rule is to check your panels’ effectiveness once a year. Longer term, it’s best to have ‘intermediate maintenance’ visits from an MCS contractor every 10 years, and a ‘full maintenance’ visit by an MCS contractor every 15 years.

When speaking to solar panel installers, it's important to ask if they offer any maintenance services and/or aftercare packages. Check out our full guide to the questions you should be asking your solar installer.

What can go wrong with solar panels?

Unfortunately, sometimes things will still go wrong in a solar panel system - especially if you've bought cheap solar panels. Some of the common things that can go wrong with a solar & battery system include:

• Damaged solar panels
• Inverter problems
• Build-up of dirt
• Battery problems

Damaged solar panels

When particularly severe storms blow, debris such as broken branches can sometimes hit solar panels and crack them.

In these situations it can be easy for panels to shatter – and the most obvious sign that this has happened will be you finding broken glass nearby. 

Damage like this will impact on your solar panel’s efficiency, and you will need professional help to fix it.

Inverter problems

While inverters generally need very little looking after, they can still fail. There can be several reasons for this: overheating, low current, faulty battery connection, low quality parts, or improper installation. 

Even without any issues, string inverters typically have a lifespan of around 15 years, with 34.3% failing at around this mark, so you are likely to need to replace one during your solar panels’ life cycle. 

Build-up of dirt

The Massachusetts Institute of Technology (MIT) revealed that a build up of dust on solar panels could reduce output by up to 30% a month.

Fortunately the UK’s regular rainfall means that dust is rarely a problem – unless you live in an area near a construction site or a mine. 

A more common issue is the build up of bird droppings and lichen, which in the worst cases can end up covering significant portions of a solar panel and reducing your system’s output. This obviously means it’s likely you will have to clean your panels at some point.

Battery problems

Battery issues can be triggered by multiple causes, such as the battery getting too hot or too cold, or being undercharged for a long period of time.

If you’re using lead batteries, this can lead to sulfation, which is a build-up of lead sulphate crystals. This can make your battery very slow to load, or stop it working entirely.

Damage to the battery will result in less electricity being absorbed, meaning it won’t be able to store as much. If the damage has been caught early on then it can sometimes be repaired, but if not it then it may need to be replaced. 

How to maintain your solar panels

Here are the key steps to take to ensure your solar panels are maintained in good working order.

Monitor their output

Reduced daylight hours means that drops in output during winter months are to be expected, but at any other time of year, a sharp drop in output may be a sign that something isn’t working properly. 

If your output looks wrong, don’t try and fix the issue yourself – it’s easy to get in a mess when dealing with wiring and connections, and it can be dangerous. It’s much safer and more reliable to have the issue looked at by a professional.

You should also check that the recorded amount of electricity being generated is continuing to increase cumulatively.

Keep them clear of shading

Overgrown trees can impact hugely on how much sunlight reaches your solar panels, which in turn reduces panel efficiency. But it’s easily solved: keep an eye on any vegetation that grows near your panels and cut it back regularly.

Keep them clean

In the UK, solar panels are deliberately fitted at angles of 15 degrees or more to ensure they will be cleaned by rainfall. This self–cleaning helps to keep panels performing at their highest efficiency. 

Having said that, if you have ground-mounted panels, which are more susceptible to a wider range of dirt due to being at ground level, or the area you live in has a high build-up of airborne dust, you are likely to have to get your panels cleaned. 

The average frequency for solar panel cleaning is once or twice a year. Assuming you can reach your panels, you can clean them with a garden hose – don’t use a pressure washer, as this may cause more damage, and avoid soap, which is likely to leave a residue. 

You can clean your roof-mounted panels with an extendable clearing brush – it’s a lot safer than going up on the roof. However, if your panels aren’t within easy reach, you should hire a professional cleaner. Individual costs will vary depending on where you live, but you can expect to pay around £10 per panel.  

It’s not recommended that you brush snow off panels as this is likely to damage them – leave the snow to melt on its own.

How much does solar panel maintenance cost?

How much you pay for solar panel maintenance will depend on whether you do the solar panel cleaning yourself, and how often you get your system professionally serviced. 

You should never climb up onto your roof to clean your solar panels, but in some cases people can clean roof-mounted solar panels pretty safely themselves using an extendable cleaning brush. Most solar panel systems need to be cleaned about once or twice a year. 

Opting for a professional solar panel clean usually costs around £100, whereas doing it yourself will come in a lot cheaper. If for whatever reason you don’t feel comfortable cleaning your solar panels with an extendable cleaning brush, you can probably expect to be paying about £3,000 on solar panel cleaning across their approx. 30-year lifespan. 

If that same solar PV system was also professionally serviced three times within its lifespan, you might expect to pay about £100 per service, or £300 across 30 years.

This means the total cost across 30 years would be around £3,300 for a 10-panel system.

How long do solar panels last?

The Energy Saving Trust advises that the average solar panel should last for at least 25 years. Having said that, many solar panels continue to work for considerably longer, with the industry average at 25-30 years, and some panels lasting for upwards of 40 years.

As mentioned, you would have to factor in replacing the inverter and battery within that time.

What's the typical warranty of a solar panel?

Solar panels come with two kinds of warranty: product, which includes the physical panel, and power output, which is how long many years can expect a certain amount of power to be generated by the panel. 

Most product warranties for solar panels are around 10-25 years, and most power output warranties are around 25 years.

Does solar panel output decrease over time?

Solar panel output is likely to decrease very slowly each year, with an expected decrease of around 0.5%. 

While this will have a minimal impact initially, it does accumulate, which is why you’re unlikely to find a warranty for solar power lasting beyond 25 years. 

Most warranties will usually guarantee 90% of maximum output for the first 10 years, and 80% by the 25th year.

Summary

Solar panels are a very low-maintenance energy option.

Of course, there are things that can go wrong, and it’s advised that you regularly check and clean your panels to make sure they are working as efficiently as they can be. 

It’s also recommended that you arrange for an intermediate maintenance visit from an MSC contracter every 10 years, and a full maintenance visit every 15 years. 

Solar panel maintenance: FAQs