We’ve created Sunsave Plus so that you can switch to solar energy without needing to have cash in the bank. Solar has the power to significantly reduce household electricity bills, and we believe this should be accessible to everyone. 

By spreading the cost with fixed monthly payments over a long period of time, we’ve ensured that Sunsave Plus is affordable for many households who otherwise aren’t able to get solar panels. 

However, we also know that your circumstances can change. And that’s why we’ve built Sunsave Plus with absolute flexibility in mind, so that it never ties you down. 

Even though Sunsave Plus starts as a 20-year subscription, you are free to make a full repayment to end your contract, or a partial early repayment to reduce the term of your contract whenever you choose. This process is simple and there are no early repayment fees or penalties. 

To make a full repayment you only pay the outstanding credit amount, you do not need to repay any future interest or monitoring and maintenance fees. A partial early repayment will shorten the term of your subscription, but your fixed monthly fee would remain the same and you will not pay any future interest on the amount you have repaid.

It’s impossible to predict the future, but we know of several reasons why you may want to make an early repayment on your subscription in future, such as a life event which means you come into money, wanting to reduce or remove future interest charges, or to shorten the contract. Sunsave Plus gives you total flexibility to do this free of charge.

You may also decide to move home during your subscription period. If this happens, you can either make a full early repayment or transfer the subscription to the new owner. To learn about the process of moving home during a Sunsave Plus subscription, check out our guide. 

Your fixed monthly Sunsave Plus payment covers repayment of the credit amount (which is the cost of the system and installation), interest on the credit amount, and a fixed monitoring and maintenance fee. 

When you make an early repayment, you reduce the credit amount outstanding. This lowers your future interest costs and shortens the term of your contract with Sunsave.

There are no charges whatsoever to make an early repayment and you can make as many as you want.

A partial early repayment is where you pay off some but not all of your outstanding credit balance. By making a partial repayment, your fixed monthly fees would stay the same but the term of your contract with Sunsave will be reduced. 

Any partial repayment you make would be deducted from the outstanding credit amount. This means you’d accrue interest on a smaller remaining balance, and pay less overall. 

If you want to end your Sunsave Plus contract, you can make a full early repayment by paying off the entire remaining credit balance. This means you will not pay any future interest or monitoring & maintenance fees that you would have incurred had your contract continued.

For example, if you were paying £69 per month then the total amount repayable on your subscription at the end of year 10 would be £8,280 (i.e. including interest and monitoring & maintenance). However, if you wanted to make a full early repayment, you’d just pay the remaining credit amount, which would be £5,683. Check out the table below to see examples throughout the 20-year period.  

<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;">Subscription timeline</th>
    <th style="padding: 12px;">Monthly cost</th>
    <th style="padding: 12px;">Total amount outstanding</th>
    <th style="padding: 12px;">Full early repayment amount</th>
  </tr>
  <tr style="border-bottom: 1px rgba(0,0,0,0.1) solid;">
    <td style="padding: 12px;">Beginning</td>
    <td style="padding: 12px;">£69</td>
    <td style="padding: 12px;">£16,561</td>
    <td style="padding: 12px;">£9,839</td>
  </tr>
  <tr style="border-bottom: 1px rgba(0,0,0,0.1) solid;">
    <td style="padding: 12px;">End of Year 1</td>
    <td style="padding: 12px;">£69</td>
    <td style="padding: 12px;">£15,732</td>
    <td style="padding: 12px;">£9,478</td>
  </tr>
<tr style="border-bottom: 1px rgba(0,0,0,0.1) solid;">
    <td style="padding: 12px;">End of Year 5</td>
    <td style="padding: 12px;">£69</td>
    <td style="padding: 12px;">£12,420</td>
    <td style="padding: 12px;">£7,923</td>
  </tr>
<tr style="border-bottom: 1px rgba(0,0,0,0.1) solid;">
    <td style="padding: 12px;">End of Year 10</td>
    <td style="padding: 12px;">£69</td>
    <td style="padding: 12px;">£8,280</td>
    <td style="padding: 12px;">£5,683</td>
  </tr>
<tr style="border-bottom: 1px rgba(0,0,0,0.1) solid;">
    <td style="padding: 12px;">End of Year 15</td>
    <td style="padding: 12px;">£69</td>
    <td style="padding: 12px;">£4,140</td>
    <td style="padding: 12px;">£3,064</td>
  </tr>
<td style="padding: 12px;">End of Year 20</td>
    <td style="padding: 12px;">£0</td>
    <td style="padding: 12px;">£0</td>
    <td style="padding: 12px;">£0</td>
</table>
</div>
</div>

If you already have a quote for Sunsave Plus and you want to work out what a full early repayment would cost you at any point in your subscription term, take a look at the chart below. It shows you what percentage of your initial credit amount would remain after each year of your contract. 

The early repayment process for Sunsave Plus is very simple.

1) contact us either by phone or email to let us know how much of your credit balance you would like to pay off early and when you would like to make the payment.

2) we’ll provide you with an exact early repayment quote within three working days (daily interest accrual calculations can be a little fiddly!). 

3) you’ll then need to confirm your acceptance of the quote at least three working days before the date you want to make the payment. 

4) we’ll process the payment via direct debit on or shortly after the date you have nominated. 

As previously mentioned, there are no penalties or fees for early repayment. 

Early repayment and the Sunsave Guarantee

If you make an early repayment then the term of your Sunsave subscription will be reduced, and correspondingly so will your period of cover under the Sunsave Guarantee. This will decrease the overall amount that you pay for monitoring and maintenance.

If you contact us to make a partial repayment, we will let you know how this will reduce your monitoring and maintenance contract length. After full repayment you will no longer be covered by the Sunsave Guarantee. 

We are working on an option to extend the Sunsave Guarantee beyond the end of the Sunsave subscription, and hope to share more on this in the future. Stay tuned!

What does early repayment involve?

Are there any penalties or fees for early repayment?

Do you lose the Sunsave Guarantee after full early repayment?

Can you reduce your Sunsave Plus payments with an initial deposit?

Sunsave Plus: a flexible way to go solar

In an ideal world, you’d make any changes to your rooftop before switching to solar, but it doesn’t always work out like that. 

Sunsave Plus means you can get a solar & battery system at no upfront cost and start saving on energy bills straight away, whereas you might not have the cash for a roof upgrade until several years down the line. 

If you choose to change your roof during the Sunsave Plus subscription, it may not interfere with your system at all, and in many cases will just cause a temporary interruption to your solar generation while the roof works are carried out. Just let us know in advance of conducting any roof works and we’ll give you a quote for the removal and then reinstallation of your solar system. 

In some cases, the changes to the roof may be so substantive that it might be tricky for you to continue with solar afterwards, but we will do our best to find a solution for you that works.

Let’s run through a range of different scenarios. 

We can temporarily uninstall and then reinstall your system

If you make any changes to your roof that mean your system needs temporarily removing, you have two options. You can either ask Sunsave for a quote to do the job, or find a different company. 

If you would like Sunsave to remove and re-install the solar system, please let us know in advance and we would be happy to provide a quote.

If you use a different company, we may need to send a roofer and an electrician to witness the process to ensure that your system remains protected under the Sunsave Guarantee, and there may be an additional charge for this.

If you’re thinking about upgrading your roof felt or tiles, in the vast majority of cases this won’t prevent you from sticking with solar. Your solar panels will need to be removed so that the felt or tiles can be replaced, but once your new rooftop is in place, the panels can be reinstalled. 

If you materially change the type of roof tile, the reinstallation of your solar panels may be a little more complicated than the first time around. For example, if you change basic clay roof tiles for something fancier like Yorkshire Stone, the panels might require different (or additional) mounting equipment and fittings, which may come at an additional charge to you.

It’s very unlikely that your new roof tiles would be completely unsuitable for solar panels. 

The elegance of a vaulted ceiling can be pretty hard to resist, and it doesn’t necessarily mean you have to say goodbye to your solar panels. Given that the work happens underneath your roof, your system won’t need to be uninstalled.

However, if your inverter and battery are in your loft, these may need to be moved to an alternative location before your loft is removed, and your DC cabling may need to be rewired. For instance, you might be able to put them in your garage, or in another room in your property. 

A vaulted ceiling can make things more difficult if your solar panels ever require maintenance, which is certainly a possibility. If the issue is external and can be solved with scaffolding then that’s fine, but if it’s a problem with the cabling on the underside of the roof then it may not be such a smooth process. 

Our maintenance team may need to construct a platform inside your home so that they could access the cabling on the underside of the roof, and may also need to remove part of the ceiling to do so. This is naturally quite a messy and expensive procedure. 

If you think there’s any chance you may want to get a vaulted ceiling at some point in the future, it would be great to know this before we do your solar & battery installation, so we can install your battery and inverter in the garage and run the DC cabling outside your property. 

Converting your loft is an excellent way to expand the living space in your property, and if it’s happening on the opposite side of the property to your solar panels then it won’t be an issue. 

However, if the conversion is happening on the same side of your roof as your solar panels, you may have to choose between one or the other. 

Your solar panels will need to be removed before the loft conversion, but getting them back onto the roof after the conversion will be very tricky, or even impossible. 

That’s because, in the vast majority of loft conversions, the new extension will have a flat rooftop, which generally won’t be suitable for solar panel installation. The solar panels would need to be secured with ballast, which would increase the weight of the system from around 20kg per panel to over 80kg, and a flat roof would not be able to support this weight. What’s more, the additional weight may eventually cause leaks, as rainwater naturally accumulates on a flat rooftop.

Most of the flat roof solar panel installations you see around the UK today are on large commercial buildings, with rooftops that are stronger and able to support the weight of ballasted solar panels. 

Even a sloped dormer roof can be an issue, as the available surface area for solar panels may be smaller than the previous roof space, so we wouldn’t be able to fit the same number of solar panels back on and your system would be much smaller. 

In the case of velux windows, it all depends on where you want to put them. If they’re part of a loft conversion, it’s highly likely you’ll also have a dormer with a flat roof, and so continuing with solar isn’t really feasible. 

If you want velux windows on an angled roof and on the same side as your solar panels, your system will need to be removed so that the windows can be installed. However, the windows will significantly reduce the available space on your roof, and so you won’t be able to reinstall the same number of solar panels. 

Even if you aren’t getting many velux windows or they’re particularly small, installation best practice means there must be 300mm of space between a solar panel and a velux window. This means you can put some of your solar panels back, but you won’t be generating as much clean electricity as before. 

In many cases, upgrading your rooftop will not interfere with your Sunsave Plus system; it will just require temporary removal and reinstallation of your system, which we would be happy to quote you for. 

If you’re planning a change to your property in the future and you’re not sure how it will affect your Sunsave Plus system, feel free to discuss it with one of our experts and they’ll be able to advise you on the best approach. 

To sign up for Sunsave Plus, answer a few quick questions below and we’ll get in touch. 

Sign up for Sunsave Plus

What happens to my solar panels if I get an extension?

Can I move my solar panels to a different roof?

Will roof changes affect the Sunsave Guarantee?

Learn about how various kinds of roof upgrade will affect your solar subscription, and how we can help.

Making changes to your roof during a Sunsave Plus subscription

Solar products that need a roof lease come with a long list of disadvantages, and many of the solar lease companies active in the 2010s caused significant problems for consumers. 

When building the UK’s first solar subscription, we wanted to keep the consumer’s best interests at the centre of every decision, and so Sunsave Plus does not need a roof lease, meaning you’ll legally own your solar & battery system as soon as it’s installed. 

In this article, we’ll run through what a roof lease is, when it’s required, what problems it can cause, and why you don’t need to worry about any of these things with Sunsave Plus. 

A roof (or airspace) lease is an agreement that gives a third party the rights to your rooftop, or the airspace above it, for a fixed period of time.

If you rent or lease solar panels from a third party, you will be required to sign a roof lease so that ownership of the solar panels doesn’t pass to you once they are installed. This is because in English property law, unless a roof lease is in place, ownership of the panels will automatically pass to the property owner once permanently affixed to the property.

After the government launched the Feed-in Tariffs (FiT) scheme in the early 2010s, leased solar products (known as ‘rent-a-roof schemes’) became a popular way for households to install solar panels. 

These lease models typically involved companies installing solar panels for free and acquiring the rights to the homeowner’s roof for up to 25 years. For the duration of the lease, the homeowner benefited from the electricity produced, and the company received the FiT payments.

At the end of the lease, homeowners usually had the option to either buy the solar panels, have them removed, or renew the lease.

On the surface, this product seemed great for homeowners who couldn’t afford the upfront cost of solar panels, but by giving up the rights to their roof they ended up facing a number of major problems. 

What are the issues with solar products that need a roof lease?

Many homeowners who signed solar roof leases in the 2010s have since experienced serious challenges, especially when moving home. 

And even though the situation has slightly improved, modern solar roof leases still come with notable drawbacks that should be avoided. 

You don’t have full control over your property

This is perhaps the most significant problem with solar products that need a roof lease, and the main reason that they have developed such a negative reputation since the 2010s. 

When a company owns the rights to your roof space, you lose your freedom to do whatever you’d like with your property and sacrifice one of the main advantages of home ownership in the first place.  

Some roof leases have clauses heavily weighted towards the company, which may be unfavourable to you (such as the roof lease agreement in this Which? article).

For instance, you may have to get consent if you want to make changes to your property, such as an extension, a new roof, or a loft conversion. 

Some leases may even require you to compensate the company for any missed export payments or lost electricity generation, and you could face penalties if any building work reduces the generation of your solar panels, even temporarily. 

You may face challenges selling your home 

Historically, prospective buyers have struggled to find mortgage providers willing to lend against homes with roof leases, as the roof lease could make it harder for the lender to repossess the home in a mortgage default scenario. 

Today, mortgage lenders have more awareness of roof leases and their key terms, however there is still considerable nervousness and they may require a lot of documents from you. Despite increased awareness, new homebuyers may still find they have fewer mortgage providers willing to provide a quote for the property. 

On top of this, new homebuyers may be reluctant to make an offer if they are planning to make future changes to the property.

If a company asks you to sign a roof lease, it is because they will retain ownership of the solar panels, and it will not pass to you.

That might sound attractive if you’re benefiting from energy bill savings and an affordable monthly payment, but you might be missing out on a huge advantage of owning solar panels; export income. 

With a solar & battery system you will produce excess electricity that you don’t need (especially in the summer months) and this is automatically sent to the grid. Energy suppliers will pay you for this electricity, and you can choose any export tariff you want - although some will also require you to be a customer. 

Export income forms a huge chunk of the financial benefit of switching to solar, and it is potentially worth hundreds of pounds a year on top of the energy bill savings. 

Some export tariffs are ‘smart’, meaning they have peak and off-peak periods, and they will automatically program your battery to import and export electricity at the most profitable times. This automated process generates additional revenue that you wouldn’t earn with a normal export tariff. Without smart battery controls, you’re not maximising the value of your system. 

Energy providers are also starting to incentivise households to use less electricity at specific hours on certain days, such as Octopus Energy’s ‘savings sessions’, where you get paid for reducing your energy usage at peak times. However, you also get paid for exporting energy at peak times, and smart battery controls can help you make the most of this opportunity. 

Currently, the only export tariff that can provide all of these benefits is Intelligent Octopus Flux, which also pays a higher rate than any other energy supplier. We estimate that a typical 5 kilowatt-peak (kWp) solar panel system with a battery could earn more than £700 per year via Intelligent Octopus Flux. 

If you choose a leased solar product, it’s possible you won’t have access to any export tariffs and you’ll miss out on all these benefits. Instead, all the export income will go directly into the pockets of the company who put the panels on your roof. 

With Sunsave Plus, you’ll own your system from the point of installation and be able to choose whichever export tariff you want. What’s more, we offer customers fast-track access to Intelligent Octopus Flux through our partnership with Octopus Energy. 

You may not be able to exit the contract 

The most restrictive roof lease contracts do not even come with a buyout clause, which means you can’t end the agreement early even if you can afford to. 

In a Guardian article from 2018 exploring the downsides of roof leases, there are interviews with several people who are trapped in long contracts and with no way to buy themselves out. 

Roof leases without a buyout clause are thankfully rare nowadays, but it’s still something to watch out for. 

As roof leases come with many negatives for homeowners, they are evidently not the best way to make solar accessible to everyone. Instead, Sunsave Plus is a highly flexible solar subscription that doesn’t need a roof lease, but still provides a solar & battery system at no upfront cost. 

Here’s how our product has been created with your best interests at heart. 

We’ve designed Sunsave Plus so that you legally own your system from day one, and it immediately becomes a part of the fabric of your property. We don’t need any rights to your roof for any period of time because the system is yours. 

This means that you’re completely free to sell your home whenever you want, unencumbered - you don’t need to check your contract or ask Sunsave for permission. 

And because our product doesn’t need a roof lease, you won’t run into any issues with mortgage lenders. They may want to check that your solar & battery system is owned by you, and that the installation is MCS certified, but you’ll have documentation from us that proves this. 

Where there are no roof leases present, mortgage lenders tend to be supportive of solar panels on properties, as they increase a household’s EPC rating, and a housing portfolio with high energy efficiency gives lenders access to cheaper, ‘green’ capital. 

With Sunsave Plus, you also have the flexibility to choose what happens when you move home: you can either pass on the agreement to the new homebuyer, or include the value of your system in the price of your property and pay off the subscription early. 

For more information, check out our detailed guides to moving home with a Sunsave Plus subscription and early repayment. 

Unlike solar products that need a roof lease, we do not retain ownership of the kit. The solar & battery system we install at your property is legally yours from the very beginning.

And because you own the system, any export income that it generates is yours. You are free to choose whichever export tariff is best for you, and in most cases we will recommend Intelligent Octopus Flux, which pays a higher rate than any other tariff and uses smart battery controls to maximise the value of your system. 

The fact you can earn export income means your system should be more attractive to incoming homebuyers, and you’ll likely see a greater boost to your property’s value whenever it comes to moving home.

Some solar products that need a roof lease are not regulated by the Financial Conduct Authority (FCA), meaning they don’t have to adhere to high standards set by the FCA when it comes to treating customers fairly. 

In contrast, Sunsave is fully authorised and regulated by the FCA, whose Consumer Duty requires us to deliver good outcomes for our customers. 

Additionally, we must demonstrate a fair relationship between the cost of our product and the benefits it provides, and all of our content must be clear and not misleading. 

What if you want roof-leased solar panels?

If you are still thinking about choosing a solar product that needs a roof lease, there are several important questions you should check with your prospective installer:

How will the product affect my ability to sell my property?

What happens if I want to make any changes to my roof or build an extension?

How will the product affect my ability to renew my mortgage or change mortgage provider?

What happens to the solar panels at the end of the lease? 

Can I exit the contract early if I want to?

If the answers to some of these questions are not what you want to hear, we recommend that you consider Sunsave Plus as an alternative. Our solar subscription is available at no upfront cost, and you legally own the system from day one (so any export income is all yours). 

What’s more, you can end your subscription early at any point with a full repayment, and if you ever want to move home during your subscription, you can pass on the contract to the new homebuyer.

Every Sunsave Plus system is also backed up by the Sunsave Guarantee, which means 24/7 monitoring, free replacement parts, comprehensive insurance provided by Aviva, and downtime cover. 

What’s a roof lease?

What are the disadvantages of a roof lease?

Does Sunsave Plus need a roof lease?

We run through the key reasons Sunsave Plus is different to a roof lease, and why this matters

Why Sunsave Plus is not a solar roof lease

Why Sunsave Plus does not require a roof lease

If you’re currently considering the switch to solar power, you’re probably encountering lots of new concepts and technical jargon. Suddenly having to hear about kilowatt-hours, inverters, export tariffs and DC cabling can be pretty overwhelming. 

We’ve built our proposal in order to make your solar transition as easy and as informative as possible, so that you know exactly what you’re getting and how much you can expect to save.

In this article, we’ll run through the key parts of your Sunsave Plus proposal and explore them in a bit more detail. 

Your Sunsave proposal is a detailed summary of the solar & battery system we’d install at your property, including a long-term forecast of how much electricity it will produce and how much money it will save you. 

The methodology for our generation and savings estimates has been checked and verified by an independent third party called the Energy Performance Validation Scheme (EPVS). Our gold membership with EPVS means we’re held to the highest possible standards. 

To learn more about Sunsave’s accreditations and why they matter, click here. 

Now let's run through your Sunsave Plus proposal. Here are the sections we'll cover:

Our price summary should show you four important figures: 

Your Sunsave Plus payments consist of three key elements: the principal, the interest, and the monitoring & maintenance fee. 

The monthly payment remains fixed throughout the 20-year subscription term, so it acts as protection against electricity price inflation (more on that further down). 

This first part of the proposal runs through exactly what your monthly price includes, so you’re clear about what you’re paying for.

Your solar & battery system will be backed by the Sunsave Guarantee. 

In an industry where companies often leave customers stranded post-installation, the Sunsave Guarantee is a monitoring and maintenance package designed to give you peace of mind. You can rest assured that your system is going to produce a steady flow of clean, green electricity for the full 20-year term of your subscription. 

To find out more, check out our guide to the Sunsave Guarantee. 

We’ll specify the type of solar panel that we’d like to install on your roof. At Sunsave, we always use black, monocrystalline solar panels, which are much more powerful and efficient than blue, polycrystalline solar panels. 

The number followed by a ‘W’ is the wattage of the solar panel, and this tells you how much electricity the solar panel can produce. For example, ten 430W solar panels equates to 4,300W or 4.3 kilowatts-peak (kWp), which means the system is capable of producing 4,300 kilowatt-hours (kWh) of electricity per year in standard test conditions. 

For more information, you can scroll down to the ‘Your kit’ section of the proposal, which also includes a link to the solar panel’s datasheet. This is where you can find lots of technical information about the solar panel, such as its dimensions, efficiency rating, and degradation rate. 

We’ll also specify the type of battery that we’d like to install at your property. A battery means that you can store up the excess electricity that your solar panels generate, ready for use whenever the sun isn’t shining. To learn more about how they work, check out our complete guide to solar batteries. 

All of the batteries we install at Sunsave are top of the range and use lithium ion chemistry, so they last longer and function much more safely than lead acid batteries.

The number followed by ‘kWh’ is the capacity of the battery, and this tells you how much electricity it can store. Generally speaking, a 5-6kWh battery is appropriate for most UK households, unless your annual electricity consumption is very high (i.e. greater than 6,000kWh). 

To learn more, scroll down to the ‘Your kit’ section of the proposal. If you want additional technical information, you can check out your battery’s datasheet.  

Perhaps the most crucial part of your solar & battery system is the inverter, which has the job of converting all the electricity your panels generate from direct current (DC) to alternating current (AC). Without an inverter, your system wouldn’t be very useful. 

The number followed by ‘kW’ is the size of the inverter, and this refers to the maximum amount of power that can be processed at any given moment. We’ll always make sure your inverter is slightly smaller than your solar panel system, as every inverter has a minimum startup voltage that it needs in order to work. If your inverter is too large, it runs the risk of not having enough power to operate effectively (especially on winter days).

If the inverter in your proposal is larger than 3.68kW, this means you’ll need permission from your local District Network Operator (DNO) before you can begin to export electricity to the grid. But don’t worry, we’ll handle the application for you. 

And whilst we wait for a response, we’ll remotely limit your inverter to 3.68kW. This means you’ll still be able to start generating and exporting electricity, just not to the full extent that your system is capable of.

Once again, if you want to know more information about your inverter, head down to the ‘Your kit’ section of the proposal and click on ‘View datasheet’. 

A chunk of your total price will go towards the cost of erecting scaffolding at your property, which is necessary for us to get the solar panels onto your roof as safely as possible. 

Similarly, your quote also includes the cost of actually installing the solar panels. Our installers are all accredited by the Microgeneration Certification Scheme (MCS), which means they comply with the highest industry standards. 

This also means your solar & battery system will be MCS-accredited, which is essential if you want to sign up for any export tariffs and get paid for any electricity you send to the grid. 

This is probably the most important part of your proposal, as it tells you how much money you can expect to save during the first 20 years of having your system. 

As previously mentioned, all of our generation and savings estimates are checked and verified by an independent third party called the Energy Performance Validation Scheme (EPVS). Our gold membership with EPVS means we’re held to the highest possible standards.

The first graph in the ‘Savings estimates’ section shows what could happen to your energy bill over the next 20 years, assuming you continue to rely on grid electricity and don’t switch to solar. The average annual growth rate of UK electricity prices between 2000 and 2021 was 5.5%, and it’s likely that this growth rate will continue over the next two decades. 

This rise was caused by underlying inflation more than it was by shifts in wholesale prices, which suggests that even if wholesale price levels remain stable or drop in the future, the cost of your energy is still likely to grow.

Another reason why energy prices might continue to climb is the ever-increasing demand for electricity in the UK (driven by electric vehicles and heat pumps), which is forecast to grow by 50% between 2020 and 2035. 

Energy market analysts Cornwall Insight also expects UK energy bills to remain high until at least the late 2030s. 

The second graph shows the same long-term rise in energy bills, but also has a straight blue line to represent the fixed cost of Sunsave Plus. As your Sunsave Plus payments remain the same throughout the full subscription term, this means you’re protecting yourself against energy bill inflation. 

In this bigger chart, we show you your new electricity costs (with Sunsave) alongside your long term electricity costs (without Sunsave). It’s a handy way of visualising the difference, and demonstrates how the value of Sunsave Plus increases over time. You can hover over the graph to get more information about what each part shows.

The reason your energy bill still increases slightly over time with Sunsave Plus is because you’ll still need to import a small portion of your electricity from the grid (more information about this in the next section). 

The chart shows that, as time passes, the gap between these two numbers will widen, which means that the amount you’re saving on your electricity bills increases each year. The gap widens sharply at the 20-year mark, which is when you will finish making your payments for Sunsave Plus. After this point, the savings you’ll make from your solar & battery system will be much larger. 

The green area between the blue and orange lines represents your cumulative 25-year savings, which is also displayed as a number in a box to the right of this chart. If your Sunsave Plus system is going to give you 1st-year savings, this number will also be shown in the same box. 

Why do you still import some electricity?

In the breakdown beneath the big graph, you’ll see that you’re still expected to import some electricity from the grid each year. This is because it’s unlikely that your solar panel system will make you fully independent from the grid all year round. 

Even if the annual output from your solar panels exceeds your average annual electricity usage, it won’t be distributed in a way that actually matches your usage. Generally speaking, about 40% of the electricity a solar panel produces in the UK is generated in summer, with the other 60% split across spring, autumn and winter. 

This means that you still need electricity from the grid in certain months - particularly during the winter season. The ‘System performance’ section slightly further down your proposal will tell you more. 

You’ll notice in your ‘Electricity cost breakdown’ that it also mentions ‘Electricity exported’. 

When your solar panels produce more electricity than your household needs, it will go into your battery - but if your battery is full, the electricity will be exported to the grid, and you’ll get paid for it.

The majority of your exports will happen in the summer, as that’s when your solar panels will typically produce much more electricity than your household and battery can handle. Exporting can still happen in the winter months, but it’s usually only for one or two hours in the middle of the day. 

However, another way you might export electricity is through ‘battery tariff optimisation’. This involves charging the battery on the off-peak rate overnight (from either your solar array or the grid), and discharging it during the peak window between 4-7pm (either to your property or the grid). This kind of battery optimisation is managed remotely by the tariff provider, and is only possible on certain tariffs, such as Intelligent Octopus Flux. 

Once your installation is complete, you can sign up for any solar export tariff, although the highest-paying tariffs require you to become a customer first. This is usually a quick and easy process, and is well worth it if you want to benefit from the best rates. 

This chart shows you the quantity of electricity you can expect your solar panels to generate in the first year, compared to your annual electricity usage.

As you can see, your system’s generation peaks in the summer months, when the days are longest, the sun is highest in the sky, and clear skies are most likely. Meanwhile, your system produces the smallest amount of electricity in the winter months.

In contrast, your electricity consumption is highest in the winter and lowest in the summer. 

This is why you’ll do most of your exporting in the summer, and why you’ll still need to import some electricity from the grid in the winter. 

This section displays our savings estimates in much more detail, so you can see what’s happening year by year. 

You’ll notice that your solar generation decreases slightly each year due to the natural degradation of solar panels, but this is entirely normal. To find out more, check out our guide to how long solar panels last. 

All of our solar panels come with a 30-year performance warranty, meaning if they fall below a certain level of output throughout this period, you will be able to get your panels replaced. What’s more, as part of the Sunsave Guarantee, we will continually monitor your system and make sure it’s working properly. 

And despite this slight fall in output, your savings will still increase each year due to energy bill inflation. 

You’ll also see that after 20 years your ‘annual cost to Sunsave’ falls to £0, which is naturally when your ‘Net savings’ increase dramatically. 

Beneath, you can find a full explanation of all the assumptions we’ve made when calculating your savings. 

Finally, our full calculation breakdown explains how we’ve estimated the output of your system. 

The table starts by telling you the kilowatts-peak of your system, which refers to the amount of electricity it could produce in standard test conditions. For example, if your system is 4.3 kilowatts-peak, this means it is capable of producing 4,300 kilowatt-hours of electricity each year in standard test conditions. 

However, the UK rarely experiences standard test conditions, which is what the rest of this section goes on to explain. 

You’ll notice that your solar panels have been put into ‘groups’. Your system may just have one group, or it could have several. A group essentially refers to a bunch of solar panels that have been wired together, known in technical terms as a ‘string’. 

It’s usually not possible to fit more than about 10 panels on one string, before having to create a new one. Most solar panel inverters can usually deal with up to three or four strings feeding into it.

Even if your solar panels can all fit onto one string, it’s sometimes a good idea to separate them into smaller strings. This is because every solar panel on one string should ideally be aligned when it comes to angle, orientation, and shading - if there’s significant variance within the string, this can reduce output. 

The orientation of the system refers to what direction your system is facing, and is expressed in ‘degrees from South’. A perfectly south-facing system (i.e. zero degrees) is optimal, but any variance from this will still be effective - providing it’s not completely north-facing.

The tilt of the system is also expressed in degrees (this time ‘degrees from horizontal’), and will almost always be the same angle as your roof. Around 35 degrees is ideal, but some variance from this is fine. 

Explore our detailed breakdown of the Sunsave Plus proposal, so you can understand every section.

Charlie Clissitt

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