Solar panels use the sun’s power to generate free renewable electricity. While the best solar panels, also known as photovoltaic (PV) panels or systems, used to take around 14 years to pay for themselves, systems installed in 2024 could pay for themselves in less than 10 years, even less if you use a solar battery.
Thousands of homeowners are switching to solar to save on their energy bills and limit their reliance on harmful fossil fuels. In this guide, we’ll outline how solar panels work, whether or not they’re right for you and, importantly, how much you can expect to save.
What are solar panels?
A solar panel is a collection of solar cells that convert daylight into useable electricity or heat. How your system does this depends on the type of solar panel you choose.
There are two types of solar panels:
- Photovoltaic panels: Produce electricity
- Solar thermal panels: Used for heating
Solar photovoltaic (PV) panels
Solar photovoltaic (PV) panels are made up of multiple cells containing conductive materials, most commonly silicon. These release electrons when exposed to sunlight, which creates a flow of energy. This energy is captured and converted, and the current is combined with the cell’s wattage to determine how much electricity is created. The most common panels used for residential solar systems are monocrystalline, polycrystalline and thin-film.
Types of solar PV cells
Monocrystalline cells. They tend to be more energy efficient, soyou’ll need fewer panels to meet your energy needs compared with their less expensive counterparts, polycrystalline panels. They’re popular with consumers who want their solar panels to look good, as their simple construction results in a sleek design. Monocrystalline solar panels are called this because their cells are made out of a single ‘crystal’ of silicon.
Polycrystalline cells. While these panels are cheaper, they are also around 13 to 16 per cent less efficient than monocrystalline panels. Polycrystalline cells also have a shorter lifespan than monocrystalline cells, and require more roof space to make room for more panels. They’re made of multiple silicon crystals which are melted, rather than cut, into squares that connect to form a solar panel which means there’s less room for electrons to move around.
Thin-film cells. The least energy efficient of the three types of solar cells, at around 7 per cent efficiency, thin-film solar panels require less material to make and are the cheapest option. Because of their lower efficiency, we usually only recommend them for large-scale commercial or industrial solar developments; they also degrade quicker than crystalline cells, so they’re not usually used in domestic setups. However, they perform extremely well in low-light conditions, and have even been found to produce electricity in bright moonlight.
How do solar panel systems work?
Simply put, solar panel are installed on a home’s roof. A solar inverter converts power from the panels into electricity for the home, and an optional solar battery can store excess electricity to be used another time. You may choose to pair your solar system with a smart meter, a device that can track your energy consumption in real-time.
Grid-connected vs stand-alone PV systems
Grid-connected. A grid-connected solar panel system is connected to the National GridIf your panels generate less electricity than your home requires, you’ll have instant access to power from the grid, which means you’ll never be without electricity. Should your system generate more electricity than your home needs, this can be exported back to the grid via your energy supplier for a profit, using the Smart Export Guarantee.
Stand-alone. Stand-alone solar PV panels are not connected to the National Grid. These types of systems are most common in remote locations where connection to the grid isn’t possible. During daylight hours, stand-alone panels generate electricity that can be used to power your home, and they store any excess electricity in solar batteries for use when your panels aren’t supplying any electricity – mostly at night. Stand-alone systems are more costly than grid-connected systems, primarily due to the cost of solar batteries.
Do I need a solar battery?
Solar battery storage systems are designed to store excess energy from your solar panels. You can then use this surplus solar to power your home at times in the day when your panels are not generating any electricity, for example at night, or in cloudy or low-light conditions.
Solar batteries are a good idea for people who don’t want to rely on grid electricity, which means being unaffected by local power cuts. However, a solar battery will set you back around £4,000, on top of your initial solar panel system investment.
What is a solar panel diverter?
A solar panel diverter redirects excess energy from solar panels to other appliances, most commonly an immersion heater, this means your boiler won’t have to work quite hard, allowing you to save even more money on your energy bills.
You could save up to £630 per year using a PV diverter, and it’ll need replacing after around 12 years.
How long do solar panels last?
Although a costly investment, solar panels for homes have an average lifespan of 25 years, and can last even longer. The best part is that you should break even on your solar panels’ initial cost long before you need to consider replacing them – and you can start earning money from them straight away through SEG (Smart Export Guarantee) payments.
Benefits of solar panels
There are pros and cons of solar panels that you’ll need to carefully consider before investing. As for the benefits, solar panels can:
- Reduce your energy bills: households with solar panels in the UK are already reducing their energy bills by up to £630 each year, or more depending on their location, solar panel system size, and how much energy they use
- Make you a profit from your excess electricity: homeowners can sell surplus energy back to the National Grid through the Smart Export Guarantee (SEG) tariff
- Increase your home’s value: potential buyers are willing to pay an average of £2,038 more for a home with renewable energy systems, such as solar panels
- Provide a constant supply of electricity: the average solar panel lasts up to 25 years or more and will generate clean energy all year round. And, providing you’ve installed a solar battery, you’ll still have an electricity supply in the event of a power cut
- Minimise your carbon footprint: solar PV panels will cut the amount of carbon dioxide (CO2) emissions your house produces. Research by the UN has found that PV panels produce between 25g and 32g of CO2 per kWh of electricity, compared to 400g/kWh for power generated by fossil fuels
Are solar panels right for you?
When considering solar panels, there are a few different factors to think about. Cost may well be the overriding factor when choosing between solar panels, but some other important aspects to bear in mind are…
- Efficiency, and what affects it: solar panels in the UK typically convert between 10-20 per cent of the energy they receive into usable electricity in the UK. Therefore, the higher percentage that your panels are rated for efficiency, the more electricity to power your home they will produce.
- Power degradation and lifespan: power degradation refers to the gradual, year-on-year loss of usable energy your panels can generate, which has a bearing on its lifespan. Solar brands will disclose this information in their product specifications and datasheets.
- Product warranty: solar panels have an average lifespan of 25 years, so suppliers should also offer a long warranty alongside them – ideally the same amount of years as the panels are expected to last. However, our researchers found that the average warranty is around 15 years, with the highest available being a lifetime guarantee.
- Size: there’s no standard size for solar panels. This means you’ll need to know your roof’s size, or have an installer measure it for you, to know how many solar panels will fit. You’ll also need to take into account how many panels your household needs in order to meet your energy consumption requirements.
Is the angle of your roof optimal?
The angle of your roof matters when it comes to installing solar panels, as it can impact their efficiency and much electricity they will produce. The geographical location of your home is also important.
The orientation and angle of your roof determines how much sunlight your solar panels will receive. The optimal angle is between 30 and 40 degrees; studies suggest that solar panels at these angles maximise sunlight exposure and subsequently generate more electricity. You’ll also need to consider which way your roof is facing, as in the UK, south-facing solar panels will generate the most energy and save you the most on energy bills.
Is your roof shaded?
After determining your roof’s angle and orientation, you should also assess how many hours a day (and at what times) your roof is shaded.
To get the most out of your solar panel system, your roof should not be shaded during peak sunlight hours; in the UK, this is between 10am and 4pm. If your roof is shaded during this time, you may not be able to generate enough electricity to power your home.
Do you have enough roof space?
Installing solar panels for your home is only a lucrative investment if you actually have enough space on your roof for the amount of panels you’ll need. Our researchers found that the average UK household requires a 4kW system, meaning you’ll need around 29m2 of available roof space.
Is your roof sturdy enough?
Unsurprisingly, solar panels add a considerable amount of extra weight to your roof. It’s easy to check how much each panel weighs before you make any big purchasing decisions, as every manufacturer discloses this information on their product specification sheets.
As an estimate, though, we’ve calculated that the average solar panel system – based on a typical UK household requiring a 4kW system made up of 16 panels – could weigh up to 280kg.
What are the best solar panels for you?
Deciding which solar panels are best for you to purchase will depend on your energy consumption, budget concerns, installation requirements and more. The best solar panels had to have efficiency ratings of over 20 per cent, and a solid power output of anything upwards of 420W.
In our research into 13 of the top manufacturers, we considered factors such as efficiency, reliability and power output to determine the best options out there. We chose The Project Solar UK Evolution Titan 445 panels as the best on the market.
How much do solar panels cost?
For a typical UK family living in a three-bedroom semi-detached house who use around 3,000kW of energy a year, a 4kW solar system is likely to be suitable. Without adding a battery, this system would cost about £7,000, and if you decide to include a battery, the total goes up to £9,000.
The cost of solar panels will vary depending on your region, energy consumption, house size, the installer and manufacturer you choose and whether you choose to add on a solar battery – which can increase your energy savings by up to 90 percent – or a diverter.
How much can you save with solar panels?
Solar panels are a long-term investment for your home that won’t pay out in a few short years. Still, there’s plenty to gain from generating your own electricity. And in the long run, solar panels won’t just pay for themselves, they could even turn you a healthy profit, too.
What is the Smart Export Guarantee?
The Smart Export Guarantee (or SEG) is a government incentive which allows UK homeowners with a solar panel system to sell their unused solar panel energy back to the National Grid in return for payments. It’s essentially like paying for electricity in reverse: you’re selling extra energy to the grid and being paid for it. Lots of homeowners with solar panels opt in to SEG payments as a way to not only save money on energy bills by using their own (solar-generated) energy, but also getting paid at the same time.
How much can you save in your area?
The below tables are examples of what you could save on your energy bills based on a 3.5kW system. These figures are from Energy Saving Trust and based on electricity prices as of April 2024.
South East London
| Amount of time spent at home | Annual savings with SEG payments |
|---|---|
| Home all day | £545 |
| Home in the mornings | £475 |
| Home in the afternoons | £450 |
| Out all day until 4pm | £375 |
| Out all day until 6pm | £345 |
Aberystwyth, Wales
| Amount of time spent at home | Annual savings with SEG payments |
|---|---|
| Home all day | £510 |
| Home in the mornings | £445 |
| Home in the afternoons | £415 |
| Out all day until 4pm | £345 |
| Out all day until 6pm | £315 |
Manchester, North of England
| Amount of time spent at home | Annual savings with SEG payments |
|---|---|
| Home all day | £505 |
| Home in the mornings | £435 |
| Home in the afternoons | £410 |
| Out all day until 4pm | £340 |
| Out all day until 6pm | £310 |
Stirling, Scotland
| Amount of time spent at home | Annual savings with SEG payments |
|---|---|
| Home all day | £475 |
| Home in the mornings | £410 |
| Home in the afternoons | £390 |
| Out all day until 4pm | £320 |
| Out all day until 6pm | £290 |
Belfast, Northern Ireland
| Amount of time spent at home | Annual savings with SEG payments |
|---|---|
| Home all day | £495 |
| Home in the mornings | £430 |
| Home in the afternoons | £405 |
| Out all day until 4pm | £340 |
| Out all day until 6pm | £310 |
When will you break even on solar panels?
While there are plenty of benefits to installing solar panels, there’s no denying that the initial investment is costly. You’ll see savings on your energy bills very quickly once your system is installed, but the amount of time it’ll take for you to break even on your initial cost is a little longer.
How soon can you break even with a battery?
Including a solar storage battery in your purchase is another way to reduce your break-even point, even though it means an even more costly initial payment. A solar battery allows you to store your electricity to use whenever you need it, including times where there is no available daylight. According to our research, around 90% of homeowners choose to include a solar battery in their purchase.
There are a few other factors that will affect how quickly your solar panels pay for themselves, including:
- The amount of sunshine and daylight your area gets
- The size and position of your roof and the number of panels installed
- The price of electricity and the SEG tariff (the amount of money you’ll be paid for the electricity you sell back to the National Grid)
- The amount of electricity your solar system generates
- Whether you utilise solar panel grants to help offset the upfront cost
Break-even point based on system size and cost
| Property size | System size | Number of panels | System cost (inc. installation and battery) | Approximate savings (inc.SEG) | Break-even point |
|---|---|---|---|---|---|
| Two bedrooms | 2kW | 5 | £7,000 | £480 | 12 – 13 years |
| Three bedrooms | 4kW | 10 | £9,000 | £960 | 9 – 10 years |
| Four or more bedrooms | 6kW | 15 | £10,000 | £1,440 | 6 – 7 years |
The UK’s continually fluctuating energy prices have a near-constant effect on the time it’ll take your solar panels to pay back. Higher energy prices mean that your system will pay for itself much more quickly; lower energy prices, along with lower SEG tariffs, will have the opposite effect.
Are there solar panel grants and financing options?
If you’re looking for solar panel grants and schemes to help with the cost of this considerable investment, there are plenty of options to look into. Government grants such as the ECO4 scheme can offer free solar panels to eligible homes, and there are other schemes and funding options available too, usually for households who are receiving income support or other benefits.
Installing solar panels
Once you’ve decided to invest in solar panels and researched the best on the market, it’s time to look into installing solar panels for your home. We’ve researched the most important questions, as well as providing a step-by-step guide to installation.
Do I need planning permission?
In most cases, you won’t need to get planning permission to install a solar panel system. This is because they are installed under the General Permitted Development Order (GDPO). However, if you live in a grade II listed building or want to install the panels on the ground rather than on your roof, you’re likely to need planning permission.
A step-by-step guide to solar panel installation
Step 1: Scaffolding goes up
A day or two before installation begins, a team will put up scaffolding around your house. This allows the installation team safe access to your roof and is a legal requirement. To avoid any unwanted fees, you should make sure the cost of the scaffolding is included in the price when you receive your quote.
Step 2: Roof team turns up
Once the scaffolding is safe and secure, your roof team will arrive with your solar panels. At this point, you should check that they have brought the correct panels: you can do this by locating the sticker on the back, which outlines the model number, make, and output.
Step 3: The anchors are attached
To attach your solar panels to your home’s roof, your installer will first need to attach anchors. The anchors are brackets that hold the rails on which your panels will be mounted. The roofers will first remove a roofing tile for each anchor and screw the anchor brackets into your roof’s rafters. The roofing tile can then be slotted back in as normal and rest onto the long arm of the anchor.
Step 4: Solar panel rails are installed
The frame for your solar panel system is made of lightweight aluminium rails, which are cut on-site by your installer to fit the size of your roof. The rails will be secured to each anchor bracket and secured with two bolts running vertically and horizontally across the roof to form a frame, on which your panels will sit.
Step 5: Solar panels are installed
At this point, your roof has now been prepared and your solar panels can be installed. Each unit will be mounted to the roof frames via a clamp. Once your installer is certain your panels are in the correct positions and are placed at optimal angles, they can be secured and tightened.
Step 6: The electrics are set up
The final step requires a certified electrician, who will connect your pre-wired panels to your solar inverter. Usually, the inverter is installed in your loft. The inverter is what converts the direct current (DC) electricity that’s generated by your solar panels into the useable alternating current (AC) electricity that will be powering your home.
How to find an installer
Now you know what to expect from the process, it’s time to look for an MCS-accredited installer.
The Microgeneration Certificate Scheme (MCS) is an accreditation that quality-assures renewable technology’s products and installers. The MCS was government-owned up until 2018, and has certified more than 4,000 contractors in the UK to date.
The MCS scheme isn’t mandatory. However, by choosing an MCS-accredited installer, you can trust they have the experience needed to do the job well. It should also be noted that, in order for your solar system to benefit from the SEG, the scheme which allows you to sell surplus energy back to the grid, your installer must be MCS-accredited.
Which companies or manufacturers are the best?
With any new investment or purchase, sometimes knowing where to look – or which manufacturers to trust – is the hardest part.
That’s why we’ve spent hundreds of hours researching different companies, manufacturers, and solar panels to find out which brands can be trusted – and which ones are most worthy of your investment – and compiled them all in our lists of the best regional solar panel installers and the best national solar panel installers in the UK.