We all know the role that solar energy plays in reducing our carbon footprint – and that the best solar panels, from an environmental perspective, are worth it. But how about from a financial perspective – and how much can solar panels save you on your electricity bills?

Below we’ll run through the factors determining how much money solar panels can save you – and what you can do to maximise these savings. We’ll also explain how to connect your solar panel system to the National Grid so you can start earning cash from your surplus energy.

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How much do solar panels save on electricity bills?

As of 1 January 2024, the price cap on electricity in the UK is 27p per kWh with an average daily standing charge of 53p. This will see the annual price cap rise from £1,834 to £1,928, a £96 increase.

Fuelled by global events, including conflict in the Middle East, the cost of wholesale gas is rising. And every kilowatt of electricity you’re able to generate through alternative, renewable methods – solar panels, for example – will offset a unit of power you’d otherwise have to purchase from your energy supplier. 

To properly answer the question of how much do solar panels save on electricity bills, let’s compare what you’ll spend without solar panels with what you’ll spend once your system is installed. 

Every home will have different levels of consumption and amounts of sunlight, so for the purposes of this comparison we have used this writer’s home in Bristol as an example. The solar panel system originally cost £5,524.00. 

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The data used to power this calculator is sourced from various solar companies and industry bodies, including the UK government, Ofgem, and the Energy Saving Trust. Please note that costs are estimated and based on a UK average, and should not be taken as the exact price you would pay. If you’d like to get an accurate quote for solar panels, then you can use this form to get an estimate from providers near you.

Cost of electricity without solar panels

We know from the MCS’s report on sunlight data for the UK that Bristol (Zone 5E) has an irradiance factor of 928. When we multiply this irradiance factor by the size of the solar panel system and make corrections for shade, we get a fairly accurate estimate of the output of a home’s solar panels. The equation looks like: system size x irradiance factor x percent shade factor = estimated annual output (in kWh).

Therefore, with a 5.5kWp system and a shade factor of zero, the equation now looks like: 5.5 x 928 x 100% = 5,064kWh in Year 1.

The total domestic power consumed from the grid at this writer’s home is estimated to be 10,276kWh over the next year. At 27p per kilowatt, this totals £2,774.52 over the year. Add in the standing charge of 53p per day, and this totals £193.45. All in all, without solar panels this writer’s house will spend £2,967.97 on electricity.

Value
Total consumed from the grid10,276kWh
Price per kWh27p
Total net price£2,774.52
Standing charge per year£193.45
Total annual cost£2,967.97

Now let’s look at how much solar panels save on electricity bills. We know that the house in our example has a system that can output 5,064kWh in Year 1 before any cell degradation. As there is no battery storage with this system, we can assume the home will consume 32% of the free electricity it generates, which is 1,620kWh. 

Cost of electricity with solar panels

Value
Estimated annual output5,064kWh
Proportion consumed32%
Annual consumption of free power1,620kWh
Savings from self-consumption£550.80
Income from Smart Export Guarantee£128.00
Total savings£678.80

So, you can see that while the solar power output doesn’t match the annual consumption, there’s a significant reduction in cost.

Plus, many UK homeowners have reported savings of up to £1,200 annually with solar systems delivering optimum output.

There’s also the Smart Export Guarantee (SEG) to factor into your savings. This allows you to sell any surplus energy back to the National Grid to boost your savings. More on SEG later.

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The investment value of solar panels

We’ve seen how much solar panels save on electricity bills. Now let’s look at their investment value.

Taking the average installation cost of £5,000 for a system this size, with £678 in revenue the Year 1 nominal rate of return will be 6.6%. We can then use this figure to project your solar panels’ return on investment going forward. 

In order to do this, however, we need to make some assumptions. First, we factor in an annual cell degradation of 0.7%, which means your solar array’s  output diminishes a little each year. We’ll also assume an RPI of 2.2% and energy inflation of 8%. (These are very conservative estimates. We know that energy prices rose 32% in 2021 and are on course to increase by another 65% by 2023. The current RPI is more than 11%. If these numbers stay at these very high levels, the return on your investment in solar will come much quicker. But for this exercise we will assume numbers more like those we’ve experienced in normal times.)

As per these estimates, the example property’s solar panels will pay for themselves in around six to seven years. 

The typical break-even point for most solar panel systems is around five to nine years, but if energy prices and inflation continue to remain high, you’ll make your money back on the investment much sooner.

And, if you live in a low-income household, you might qualify for grants for solar panels in the UK – such as the Energy Company Obligation 4 (ECO4), which runs until March 2026 – to make your solar system much more affordable; and your break-even point even sooner.

When do solar panels pay back?

There’s no straightforward answer as to how long it will take for solar panels to pay back, as there are a number of factors that can impact this: including the initial cost of your system, your household’s electricity usage and where you live.

However, we’ve done some research to find out how much money you can save on your energy bills with various system sizes and compared this with their average cost to determine how long it takes to recoup the investment.

What we found? That most solar panels will pay for themselves within a decade.

System sizeNumber of panelsTotal cost (inc installation)Potential annual energy bill savingsPayback period
3kW12£5,700–£6,700£9006–7 years
4kW16£6,800–£8,800£1,0007–9 years
5kW20£9,000–£10,000£1,1008–9 years
6kW24£10,200–£11,200£1,2008.5–10 years
Approximate prices for December 2022. Source: Federation of Master Builders

How to consume more of your free solar energy

When it comes to accessing clean, green solar energy for your home, it’s not just generating that power that’ll save you money – it’s maximising your use of it, too.

So how can you ensure you’re making the most out of your domestic solar array? Let’s explore.

photo of bournemouth seafront at sunset

The sun is a source of free energy that we can all use (Image credit: Adobe)

The impact of location

Living in the south of the country can boost your output by up to five per cent compared with the north.

That means that where you live within the UK will have the most impact on how much solar energy you generate and consume – and, of course, how fast you make your money back. The further south you live, the more sunlight your panels will be getting. In London or further south, you might find your savings from solar panels are about 10% higher than in Manchester.

Work from home during the day

If you work from home, you can also expect better savings. Simply being in your house all day means you’re using more of that free renewable energy. And the more solar energy you consume, the more you save on your electricity bills and the faster you make your money back on the investment. 

The flip side of being home all day means that you won’t have as much surplus energy to sell back to the National Grid. But with energy prices as high as they are, the money you’d earn from the Smart Export Guarantee will likely be less than what you would save by not having to pay your energy provider. You’re paying 27p per kilowatt-hour for electricity right now, but you’ll be paid a lot less than that for every kilowatt you sell back to the grid. 

You should also aim to use your white goods during the day as much as possible, when electricity is off-peak and thus at its cheapest. If you have to go to an office, work it into your morning routine to run the dishwasher before you go and program your washer to do your laundry in the afternoon. Little things like this really add up over time. 

If you want to consume even more of the electricity you generate, it’s worth considering investing in a battery. 

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Are solar batteries worth it? 

This is a matter of hot debate, with many people waiting to see what the market does.

To maximise your savings, you want to use as much of your ‘free’ generated power as possible. But even as a high-energy user, there will be periods when you’re drawing a background load only. Adding a battery to your system allows you to store all of your excess power to use later, significantly increasing your self-consumption and boosting your savings. 

Is it worth installing a solar battery? 

Solar batteries remain very expensive. The average battery costs anywhere between  £2,000 and £7,000, with some high-end models costing in the region of £10,000 to £12,000. They last about 15 years, and their capacity decreases slightly near the end of their life. When you consider that the average annual savings from a solar battery is around £300 (based on energy inflation in normal years), the maths, right now, simply don’t add up to make the investment worth it.

However, that might be starting to change.

Many have been waiting for solar battery prices to drop before making the investment, but the soaring price of electricity might push the needle from the other direction. The more excess energy you can store in your battery, the less you’ll need to pay your energy supplier at exorbitant rates, and the more you can sell back to the Grid. If electricity prices creep higher – or even remain at what they are in 2024 – the return on the investment of a solar battery will be much sooner. 

The Smart Export Guarantee

The Smart Export Guarantee pays the average solar panel owner in Great Britain £120 to £180 per year.

To earn money from your solar panels you need to apply to join the SEG. It requires electricity suppliers who are registered with the scheme to pay small-scale generators of low-carbon electricity for any energy they export back to the National Grid. Homeowners with solar panel systems of five megawatts or less can apply to join the scheme.

To join, you’ll need to apply directly with an SEG provider. SEG providers are any energy supplier with more than 150,000 customers. By law, they’re required to offer you a per kilowatt-hour rate for your surplus electricity. Rates vary, with EDF offering 3 to 5.6p and Octopus Energy providing 4.1p per kWh.

To qualify for the scheme and receive payments, you need:

  • to prove that your system was installed by a solar panel installer certified under the Microgeneration Certification Scheme (your installer would have given you a certificate evidencing this); and
  • a smart meter to track the amount of energy you export to the grid. You’ll need what is called a SMETS 2 meter, the second generation smart meter. 

The SEG replaces the popular Feed-In Tariff (FIT) scheme, which ended in 2019. The FIT scheme pays households a stipend for every kilowatt of solar energy they generate, plus a separate fee for every kilowatt they sell back to the National Grid. The scheme still exists for those who joined before 2019, but it is now closed for new entrants.

Solar Panel FAQs

A solar panel with a 300 W-rating (a common choice for UK homeowners) costs between £200 and £300 in the UK. So, for the total solar system, typically a 4 kW install, the cost is around £5,500.

A system with this amount of power output will require around 30m² of roof space. More powerful systems will require panels with higher energy-producing potential and/or larger roof space. Ground-mounted solar panels – arrays fixed to poles or purpose-built racking systems – are an excellent alternative for properties with abundant land or limited roof space.

The above example of a 4 kW system would cost around £600 to £1,000 to install, depending on location and roof type. More powerful systems usually take longer to install and will therefore cost more, at a rate of around £300 per person per day; solar panel installation is usually a two-person job.

A typical 4 kW system, using 300 W-rated solar panels, will need 16 solar panels and take up about 30m² of roof space. Naturally, more powerful systems will require more roof space or more powerful panels (or both), depending on power output you need. For example, a 6 kW system might need 24 solar panels, taking up 43m² roof space.

This depends on your roof size, geographic location, and budget. We recommend the Project Solar Evolution Elite 400 as the best all-round option, as well as the SunPower Maxeon 3, which has fantastic efficiency. The LG NeON H BiFacial has excellent output and is ideal for period or listed properties thanks to its low profile.

Like buying an electric car, solar panels require a large investment at the outset. However, they require little to no maintenance in the long-term – and will save you money on your electricity bills. You can also earn money on the surplus energy you don’t use by selling it back to the National Grid under the Smart Export Guarantee. 

When you factor in SEG earnings and the savings you’ll make on your electricity bill, solar panels can be extremely profitable over time, and most people make a return on their investment within seven years.

How much solar panels save on bills depends how large your system is and how often you’re at home to use the energy. Some people have the space to install systems that can power their entire home.; although the average solar panel system provides around 50% of the energy a home requires. 

Even taking 50% off your electricity bill makes for huge savings over time. However, if you work in an office and no one is at home during the day to use the electricity you generate – and if you don’t have a battery to store this energy and maximise those savings – there are some things you can do. 

One such strategy is utilising the in-built timers most household appliances come with. Take advantage of these by setting them to start in sequence during the day. That way, you’ll be using less of the supplied electricity when you’re home from work in the evening.

Jeff is a highly experienced editor and journalist with extensive experience in the tech industry, as well as for the automotive and DIY sectors, writing for both B2C and B2B brands.

Jeff has tested all manner of tech, from cameras to phones to EVs and home appliances. In his 23 years as a writer and editor, Jeff has written for global tech titles like TechRadar and Digital Camera World, as well as brands such as eBay, Canon, Panasonic, Eero, and many more. In addition to editorial, Jeff also has many years experience producing video and podcasts. He is also passionate about renewable energy and green living, and explaining this technology to new audiences.

Contibutions by Rob Binns

Rob has written for publications such as Eco Experts, Home Business, Expert Market, Payments Journal, and Yahoo! Finance as a renewable, smart home technology, business software expert.