☀️ Modern solar panels have a lifespan of around 30-40 years

📊 Monocrystalline solar panels last longer than polycrystalline

⏳ Solar panel lifespan has improved in the past few decades

📉 Solar panels degrade each year, but only very slightly

🛡️ There are steps you can take to ensure your panels last as long as possible

Given that solar panels are supposed to be an investment with a financial return, it's important that they last a long time. Nobody is paying for all that scaffolding, labour and hardware only to have their system give up the ghost after just a few years. 

Wondering how long solar panels tend to stay at their best? This article will explore all the factors that can affect the longevity of solar panels, from installation to maintenance and beyond.

And if you’re wondering how much a solar & battery system could save you, just answer a few quick questions below and we'll generate an estimate for you.

What’s the average lifespan of a solar panel?

A modern, monocrystalline solar panel usually lasts around 30-40 years, depending on its quality, the conditions it has to endure, and how well it's been maintained.

However, it doesn't necessarily mean that a solar panel completely shuts down and stops working between year 30 and 40. A solar panel's efficiency (and consequently its output) falls by a very small amount each year, and so it just naturally reaches a point where output has fallen too low for the panel to be worth having. 

Saying that, there are some very impressive solar panels at Oldenburg University, Germany that have been generating electricity since 1976 (and were moved in 1981 to the Energielabor building). 

We spoke to a representative from the university, and they said: “Most of the photovoltaic modules installed at the Energielabor in 1981 are indeed still working; they feed more than 3,000 kilowatt-hours of electricity into the grid per year.”

Considering these 336 solar panels had a power rating of 3.46 kilowatt-peak (kWp) when they were initially set up, this shows some serious durability. Between 1976 and 2011, the system’s efficiency rating only dropped from 8.55% to 8.2%.

Perhaps not every solar panel will last 50 years, but it's also too early to say quite how long this modern generation of monocrystalline solar panels will live for. 

As long as your solar panels are good quality and you've kept on top of your solar panel maintenance, your system should continue to function beyond its warranty.

Solar panels usually come with two types of warranties:

The product warranty covers defects in the solar panel itself and typically covers around 20-25 years, although some manufacturers offer longer warranties up to 30 years or beyond.

The performance warranty guarantees that the solar panels will produce a certain percentage of their rated power output over time, usually promising around 80-90% of their original output by the end of the warranty period.

Solar panel warranties go some way in protecting your investment, but it's not advised to rely on them as your only source of maintenance support. If anything goes wrong with your system that isn't the fault of the manufacturer, they won't help, and even if it is their fault, the process of making a claim can be very arduous. 

That's where the Sunsave Guarantee comes in - a comprehensive, 20-year maintenance package for every Sunsave Plus solar & battery system. Find out more here. 

If one of your solar panels has an issue that you believe to be the fault of the manufacturer, you can claim on your solar panel’s warranty, but this usually involves quite a lot of time and effort. As part of the Sunsave Guarantee, we’ll take care of any solar panel warranty claims so you won’t have to lift a finger.

Monocrystalline vs polycrystalline solar panel lifespan

If you've started doing your research before making the switch to solar, you may keep seeing these two rather long words cropping up online: monocrystalline and polycrystalline. 

These terms are referring to the two main types of solar panel on the market right now. 

Polycrystalline solar panels are older, less technologically advanced, blue in colour, and cheaper. They're made by melting multiple silicon crystals and combining them in a square mould.

Monocrystalline solar panels are newer technology, black in colour, and a bit more expensive. They're made from single-crystal silicon. 

These panels differ in terms of quality, and so naturally they have different lifespans. 

Black monocrystalline solar panels tend to last between 30-40 years, although most don’t come with warranties that exceed 30 years. Meanwhile, blue polycrystalline solar panels will start to struggle slightly sooner - usually at the 25-year or 30-year mark - and these come with a shorter warranty. 

If you want panels that are going to last for the long haul, definitely choose monocrystalline.

To find out more, check out our guide to why black solar panels are better than blue.

Solar panel lifespan has certainly improved, but it's been very good for a number of decades. These big slabs of silicon have no moving parts, which means they can sit under the sun for a long time without the risk of much going wrong.

As mentioned earlier, there is a solar panel array at Oldenburg University, Germany that was installed in 1976, and is still producing a decent amount of electricity today. 

A 2017 study conducted by the National Renewable Energy Laboratory (NREL) found that the failure rate of solar panels installed between 1980 and 2000 was twice as high as the failure rate of solar panels installed between 2000 and 2015. In this study, 'failure' is defined as when a panel had to be completely replaced. 

This clearly shows significant improvement in the 35 years between 1980 and 2015, and the endless development of solar panel technology by manufacturers will surely only lead to further durability gains. 

To learn more, check out our article about whether solar panels are improving. 

Curious about the savings you could get from a solar & battery system? Answer a few quick questions below and we’ll provide an estimate.

Do solar panels degrade over their lifetime?

Yes, a solar panel goes through a natural degradation process as part of its lifecycle. This means that its ability to convert daylight into electricity is very slightly reduced each year. 

Physical degradation is simply an unavoidable fact of solar panel existence - just like ours.

There are various things that cause it, and most of them aren't preventable. For example: internal wires experiencing wear and tear, and long-term exposure to UV rays causing the backsheet to break down. You could hide your panels from the UV rays to protect the backsheet, but then you won't be generating any electricity. 

Other causes are a bit more dependent on the environment your solar panels are placed in, and how often they're cleaned, such as: metal frame corrosion, and debris or hail creating tiny cracks in the surface of the panel (which can affect electrical connections). 

How much do solar panels degrade each year?

Generally speaking, the degradation rate of monocrystalline solar panels is 0.5% per year. 

This means that, after 30 years, most monocrystalline solar panels on the residential market will produce 87% of their original power output. 

To learn more about solar, check out our rundown the top 17 facts about solar panels. 

Typical degradation of a solar panel over 30 years

How to make your solar panels last as long as possible

If you want your solar panels to last and perform well, you need to take care of them properly. There are important steps you should take before you get the panels installed, and things to stay on top of once the panels are up on your roof. These are:

There's no point paying a premium for top-tier hardware only to have the installation bungled by sub-par installers. 

Choosing an experienced, trustworthy installer with all the right accreditations significantly decreases the chances of problems further down the line, and ensures that you'll get the best out of your system. 

Always make sure your installer is either accredited by the Microgeneration Certification Scheme (MCS) or Flexi-Orb, as a minimum. On top of that, look out for seals of approval from industry bodies like HIES, Trustmark, and NAPIT, as well as savings estimates that are checked by the Energy Performance Validation Scheme (EPVS). 

If that's not enough, keep an eye out for installers that have been approved as a Which? Trusted Trader, as this means they've been through several rigorous rounds of assessment. 

And last but not least, have a look at the installer's reviews on websites like Trustpilot. 

To find out more, check out our guide to the best solar panel installers in the UK. 

Every solar panel system comes with an inverter (otherwise it won't work), and every inverter comes with a mobile app that lets you monitor your system's output. 

Seasoned solar panel owners often speak with great delight about their solar panel app, because each one is usually full of colourful charts, live data, and understandably it can get pretty addictive. Particularly if it's telling you every day how much money you're saving. 

It's useful to keep an eye on your app and make sure that your solar panel system's output looks normal, because a dramatic drop will signify that something is wrong, and you're unlikely to notice a drop just by looking at your panels. 

What is 'normal' output, you ask? In the first few months of having your system, you can compare your system's actual generation with what your installer has predicted - and check if it stacks up. Then, once a few years have passed, you'll be more familiar with what to expect. 

Rather not take on that responsibility? Sunsave Plus is the UK's first solar subscription, and every Sunsave Plus system is protected by the Sunsave Guarantee. This includes 24/7 monitoring and maintenance, so our solar experts will remotely keep an eye on your system, troubleshoot any problems and, if necessary, come round to fix things. Click here to learn more. 

Solar panels are known as 'self-cleaning', which sounds a little more hi-tech than what's actually happening. They have a waterproof (or 'hydrophobic') coating, just like your anorak, and they're installed at an angle, so whenever it rains, rainwater just rolls right off them.

And if there's any dust or dirt on your panels, most of this should be removed by the rainwater. 

So a solar panel's 'self-cleaning' technology isn't quite so effective in very dry countries (well done, UK). 

However, despite a solar panel's water resistance, we still recommend that you clean your panels every two or three years in the UK. And if you live right next to dusty farmland or right by the sea, more frequent cleaning is a good idea. 

That said, don't risk the danger of climbing onto the roof to do so - instead, we recommend using an extendable soft brush from ground level, or calling in a professional (rough cost is about £10 per panel). Many window cleaners around the UK also offer solar panel cleaning as a service.

If you don't keep your panels clean, the build up of dirt will affect their output and potentially cause them to deteriorate faster.

To learn more, check out our guide to solar panel cleaning. 

Technical experts in the industry estimate that a solar & battery system will require three maintenance call-outs in 20 years - one for the panels, one for the battery, and one for the inverter. 

So even though solar panels are made of sturdy stuff and have no moving parts, this doesn't mean they don't encounter issues. 

At the very least, the MCS recommends that you have a professional conduct a basic inspection of your panels every 10 years, and a more comprehensive on every 15 years. 

However, you're not likely to catch and solve any issues if someone's only looking at your panels once a decade. Solar panel maintenance is important, and it means you always get the best out of your system. 

For a proper maintenance support package that'll do the business, check out the Sunsave Guarantee. 

Next steps

Solar panels are built to go the distance, so you can expect a set of good, monocrystalline panels to last around 30 or more years. 

But things can still go wrong, and there are steps you can take to ensure that your panels last as long as they possibly can. 

Look after your panels, and they'll look after your bills. 

To find out how much a solar & battery system could save you, enter a few quick details below and we'll generate an estimate for you.

Solar panel lifespan: FAQs

What is the average lifespan of a solar panel?

How often do solar panels need to be replaced?

What happens after 25 years of solar panels?

Can solar panels catch fire?

Do solar panels need cooling?

How long do solar panels last? | Average lifespan [2025]

What's in this article?

How long do solar panels last?

⚡ A 4.4kWp solar panel system typically generates 3,740kWh per year in the UK

☀️ Solar panel output varies according to multiple factors

✂️ A solar & battery system can cut your electricity bill by 86%, on average

🏖️ Solar panels produce much more energy in summer

📈 You can help to maximise your system's output

It’s widely known that solar panels generate electricity and reduce people’s reliance on the national grid, but how much electricity do they actually produce? Is it reasonable to expect solar panels to completely cover your electricity needs? 

In this article, we'll explore roughly how much electricity a solar panel system can produce, and explore the various factors that can influence solar output. 

If you’re interested in switching to solar, you can find out how much a solar & battery system could save you by answering a few quick questions below.

What’s the typical output of a solar panel system?

A solar panel system in the UK will typically generate around 85% of its peak output.

This is based on the level of solar irradiance at Dunsop Bridge, a village in Lancashire which the Ordnance Survey has declared the geographic centre of Britain.

If you live south of this location, you can expect more solar irradiance, while places to the north will usually receive less, though this isn't always the case, and there are other important factors that we discuss further down.

If a system has a peak rating of 4.4 kilowatts-peak (kWp), it would produce 4,400 kilowatt-hours (kWh) per year in standard test conditions (STC), which is a set of environmental factors used across the industry to measure a panel's capabilities.

But since the average conditions in the UK are around 85% as good as STC, these panels will produce around 3,740kWh per year.

This is more than enough for the average household, which typically uses 3,400kWh of electricity per year, according to government data.

Typical solar panel output by system size, UK

As well as the average irradiance mentioned above, this chart also assumes you have a south-facing roof with no shading.

As you can see, the main factor behind how much energy your panels generate is the size of the system, which makes sense – the bigger and better your system, the more electricity it'll produce.

But even with identically sized systems, you can see massively different output levels. Check out a few examples here:

<div style="text-align: center; font-size: 14px;">
<div style="display: inline-block; border-radius: 8px; overflow-x: scroll; max-width: 100%; margin: 40px auto; text-align: left;">
<table style="background: rgba(0,0,0,0.02);">
  <tr style="background: #4EE5D3; text-align: left; border-radius: 4px;">
    <th style="padding: 12px;">Location</th>
    <th style="padding: 12px;">System size (kWp)</th>
    <th style="padding: 12px;">Annual output (kWh)</th>
    <th style="padding: 12px;">Annual consumption (kWh)</th>
  </tr>
  <tr style="border-bottom: 1px rgba(0,0,0,0.1) solid;">
    <td style="padding: 12px;">Exeter</td>
    <td style="padding: 12px;">4.3</td>
    <td style="padding: 12px;">4,665</td>
    <td style="padding: 12px;">4,750</td>
  </tr>
  <tr style="border-bottom: 1px rgba(0,0,0,0.1) solid;">
    <td style="padding: 12px;">Norwich</td>
    <td style="padding: 12px;">4.3</td>
    <td style="padding: 12px;">3,767</td>
    <td style="padding: 12px;">2,401</td>
  </tr>
  <tr style="border-bottom: 1px rgba(0,0,0,0.1) solid;">
    <td style="padding: 12px;">Peterborough</td>
    <td style="padding: 12px;">4.3</td>
    <td style="padding: 12px;">3,668</td>
    <td style="padding: 12px;">3,654</td>
  </tr>
  <tr>
    <td style="padding: 12px;">Wigan</td>
    <td style="padding: 12px;">4.3</td>
    <td style="padding: 12px;">3,629</td>
    <td style="padding: 12px;">3,500</td>
  </tr>
</table>
</div>
</div>

Despite all of these systems being in different places in the UK, location is not the only variable at play here.

Your system's output will also be affected by differences in roof orientation, angle, shading, and what type of inverter the system has.

🤔 Thinking of going solar? Here's why a larger system makes sense ⬇️

How much will this save you on your energy bills?

On average, you could save 86% on your electricity bills with a solar & battery system. 

This figure is based on a sample of over 150 systems installed by Sunsave across England and Wales in 2024. The average system is 6.1kWp, with 54% of solar electricity used at home and 46% exported to the grid.

How much energy do solar panels produce per day?

A 4.3kWp solar panel system will produce 10kWh per day in the UK, on average.  

However, you shouldn't take this as a hard-and-fast rule, because your system's daily generation levels will vary massively, due to a host of factors.

As well as the variables listed above – like orientation, angle, shading, and inverter type – generation will also be affected by each panel's peak output, their location, the weather, and what time of year it is, as this will determine how many hours of daylight there are.

So on average, a 4.3kWp solar panel system in London will produce 8.8kWh per day, while the same system in Exeter will typically generate 12.8kWh per day.

If it's in the ideal situation though, on a south-facing roof with an orientation of 40°, it'll produce even more solar electricity.

And wherever you are, your output will likely be around 55% below the average in winter, and 52% higher than average in summer.

As a result, you'll usually have to buy grid electricity during the colder months to make up the shortfall, but you can then sell your solar energy to the grid when summer comes round again.

At Sunsave, we have a gold membership with the Energy Performance Validation Scheme (EPVS), which means all of our savings estimates follow a methodology that has been validated by an independent third party. Whichever installer you choose, make sure their estimates are EPVS-approved.

How much energy do solar panels produce per hour?

Solar panels produce 0.8kWh per daylight hour, on average.

Your daily solar output will be higher than this average in summer, when there are more daylight hours, and lower than average in winter. We'll go into more detail below.

Your solar panel system will be most productive at solar noon, when the sun is at its highest point in the sky. Due to the nature of the Earth's orbit, this time is almost never exactly 12pm, but instead occurs between 11:40am and 1:10pm, depending on the time of year.

You should therefore concentrate as much of your electricity consumption as possible during this time and the couple of hours either side, to take advantage of your increased solar output. Run the dishwasher, do the laundry, cook dinner – whatever makes sense for you.

Though of course, if you have a solar battery, you can simply store the extra electricity and use it later.

The UK's first solar subscription

The average solar panel output per m² is 186kWh per year.

Solar panels are usually around 2m², which means the typical 430-watt model will produce 372kWh across a year.

A solar panel system will need space on either side, so finding out your roof's area is only one part of working out how much solar electricity you can generate, but it's a great first step.

<center><em>If you have a big roof, you can profit by exporting even more electricity to the grid</em></center>

A solar panel system does not consistently produce the same quantity of electricity throughout the year. In the summer months when the sun is high in the sky (and the days are long), solar panels are at their most productive.

And conversely, in the winter months when the sun is low in the sky (and the days are short), solar panel output drops quite significantly. 

For example, consider the below output chart, which is based on a four-bedroom home in Essex with a 6kWp solar panel system and 5kWh battery.

The system generates almost 25kWh of electricity each day in May and July, but produces just 4.9kWh per day in December. 

Broadly speaking, a solar panel system in the UK will produce about 70% of its total output in spring and summer (March to August), with the remaining 30% coming in autumn and winter (September to February). 

The chart below should give you a rough idea of how productive your solar panel system will be across the four seasons (ranging from around 11% in winter to almost 38% in summer). 

Solar panel output: UK vs Europe

Solar panels can produce more than enough electricity in the UK to help people significantly reduce their energy bills, despite the fairly cold and cloudy weather for much of the year.

Check out the chart below to see how solar panel energy yield in the UK compares to that of other countries. This is measured in kWh / kWp, which refers to the quantity of kWh that will be produced from one kWp of solar PV, based on the level of solar irradiance.

You'll notice that the UK certainly isn't the worst of the bunch, and is only 124 kWh/kWp behind France. 

What factors affect how much energy solar panels can produce?

There are 10 key factors which affect solar panel power output:

Let’s explore these factors in more detail.

When it comes to solar panels, 'power' refers to the maximum amount of electricity a panel can generate (in watts). The panel's 'efficiency' is all about how effectively it can convert daylight into electricity.

Higher power and efficiency mean greater electricity production. This means that, in the exact same conditions, a 430W solar panel with 22% efficiency could generate more electricity than a 350W solar panel with 20% efficiency.

Like all electrical systems, solar panels degrade over time, which means they'll generate slightly less electricity as the years go by.

The average solar panel system in the UK loses between 1% and 3% in its first year, then around 0.5% with each subsequent year.

That means after 25 years, the average system will produce 14% less energy than it did on its first day.

Degradation is more of an issue for solar panel systems in hotter climates, where the heat can negatively affect electrical networks.

Typical solar panel degradation over 30 years

Solar panel systems are complex networks of electrical equipment that can underperform or malfunction if installed incorrectly.

If your installer doesn't secure the connections between the solar panels and inverter and the inverter and fuse box, your system may not convert DC electricity to AC electricity – which is the type your home runs on – or send all of the converted electricity to your home's devices.

And if they don't connect the diodes properly, your system could produce less solar electricity or be damaged by the battery discharging to the panels at night.

At best, bad connections will mean you get less solar electricity. At worst, a faulty connection can start a fire.

Shade can have a pretty significant impact on solar panel output, which is why it’s important to make sure there are no trees towering over your solar panel system. 

When solar panels are installed using a traditional string inverter, they’re connected in ‘strings’ (usually around 8-14 panels per string). If something is casting shade on one panel and reducing its output, this will have a detrimental effect on the electricity generation of the entire string.

This is where microinverters come in handy (more on that below).

Solar panels are built to withstand extremely hot weather, which is why there are very productive solar farms located in some of the hottest places in the world. 

However, solar panels still see a very slight drop in output once they get particularly hot - in fact, every solar panel loses a tiny sliver of generation for every degree above 25°C. On a solar panel's datasheet, this is called its temperature coefficient. 

To clarify, this coefficient refers to the temperature of the solar panel, not the temperature of the air around it.

The average temperature coefficient for a solar panel is -0.32%/°C, which means for every degree above 25°C, a solar panel's output falls by a miniscule 0.32%. 

However, even if your solar panels were to reach the dizzying heights of 50°C, they would still be operating at roughly 92% of their original capacity - not a very significant loss at all.

Typical solar panel output loss in high temperatures

Solar panels all have a hydrophobic coating, meaning they are essentially self-cleaning. When rainwater lands on a solar panel it rolls right off it, in theory taking any dust or dirt with it. 

However, in certain areas, solar panels can accumulate enough grime that it limits the amount of daylight that can hit the panels.

This phenomenon, which is known as solar panel soiling, can be brought about by detritus as diverse as dust, exhaust fumes, agricultural emissions, and organic material like bird droppings, lichen, and pollen.

In the UK, solar panel soiling can cut your system's output by more than 5%, according to Loughborough University, but it's a far more serious issue in hot, arid areas like China, India, and the Middle East, where losses can reach 70%.

Keep an eye on your solar panels, and get them cleaned every time they get noticeably dirty.

Never climb up on your roof to clean your solar panels (for obvious reasons)! Instead, you should get a soft, extendable brush that you can use from ground level - this will probably cost about £100. Alternatively, you can sit back and pay professionals to do it, who typically charge about £10 per panel.

As mentioned above, if one panel in a string inverter setup goes south, it'll mess up the whole string's output. With microinverters, each panel gets its own dedicated inverter and operates independently, so any malfunctions won't affect the entire system.

It’s also possible to stick to a normal string inverter and add optimisers, which are designed to improve the performance of the weakest panels in a system. 

Your system's output could also be affected by solar inverter clipping, which is when your panels produce more electricity than your inverter's peak rating. As your inverter can't process the extra energy, it'll turn into heat and be lost to you.

 Correctly sizing your inverters will avoid this happening too often, but don't spend too much in an effort to eradicate all clipping. In many cases, a small amount of clipping over the sunniest months is worth avoiding spending hundreds of pounds on more powerful inverters.

However, buying an efficient inverter is a good investment. Solar inverters are usually between 93% and 98% efficient at turning DC electricity into AC electricity, which is a large enough range to make a significant difference to your output.

The angle and direction of solar panels has a big impact on their output. Aim for the sweet spot: facing south and tilted at an angle matching your latitude. The best angle for solar panels in the UK is around 39 degrees, according to a 2019 study from York University.

Solar panels can still be very effective if they’re east-facing or west-facing though – it’s just that south-facing is the optimum scenario. Any solar installer worth their salt will design a solar panel system for your property that makes the best use of your available roof space.

Whatever direction your solar panels face, some sunlight will reflect off them instead of being absorbed, reducing their output by around 2% to 4% – or it would, except more than 90% of commercial modules now come with anti-reflective coating.

The coating eliminates the great majority of this loss, so make sure it's included with any panels you buy.

The impact of angle on solar panel output

This chart shows the average of 26 solar panel systems in Yorkshire, all with a peak power rating of 4kWp.

The best angle is clearly 39 degrees – and though this varies a little as you move around the country, the difference is always minimal.

You won’t be surprised to read that sunshine makes a difference to solar panel output, and the UK sees a pretty wide range of solar irradiance. In the south of England there is an average of 128.4 watts per square metre (m²), whilst in the northwest of Scotland it’s just 71.8m².  

But despite the south coast of England seeing more sunshine than anywhere else in the UK, you can still have a productive solar panel system in any part of the country. Plentiful sunshine is a bonus, but not a key ingredient – and you can see from this list just how many other factors determine how well a solar panel system works. 

Your inverter will usually contain a transformer, which performs a vital function that does unfortunately result in some energy loss.

The transformer converts incoming DC electricity to AC electricity you can use in your home, and also changes the voltage of that energy to match that of the appliances your solar energy will then power.

Unfortunately, like all electrical products, it does produce a small loss in energy – about 1%, usually – because it involves multiple complicated processes. 

Some inverters now come without transformers, which avoids this loss – but they're not common just yet.

How to ensure your solar panels produce more energy

If you’re considering having a solar panel system installed, there are a few things you do in order to maximize its output. For example: 

Discover the typical electricity output of a solar panel system in the UK – per year, per day, and per hour – as well as what affects it.

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