Your solar & battery questions, answered

If you’re nearly ready to take charge of your energy supply by getting solar panels installed at home, but need a hand deciding if it’s the right time for you - then look no further. At Octopus, renewable energy is our bread and butter.

We’ve asked our experts to answer your most frequently asked questions, to help you decide if it’s time to join the race to net-zero, and begin generating your own clean, green solar power at home.


What to expect from your solar installation

The big day has arrived, but what does it involve? We talk you through the process step by step.


More questions? We've got you covered:

How does home solar power work?


infographic for solar2

  1. A solar panel’s photovoltaic (PV) cells convert the particles in sunlight into a direct electrical current (DC). This current travels down through the cables, into your home.
  2. The inverter converts this direct current (DC) into an alternating current (AC). This electricity can then be used straight away to power lights & sockets around the home.
  3. Once the house has all the power it needs, excess energy can be stored in the battery for use when the sun isn’t shining. If you don’t have a battery, this electricity travels directly to the smart meter.
  4. From the electricity meter, any energy that hasn’t been used or stored can be sent back to the grid. Here the smart meter will record how much energy has been exported so that you can be paid for it later.
  5. All of the clean, green energy you generated but didn’t use is distributed to other homes in the area.

    Find out how this works on a bigger scale here.

Are solar panels right for my home?


Before going ahead with your installation, we'll need to make sure solar works for you.
Firstly you will need a clear space on a pitched (not flat) roof that can fit at least 4 solar panels. (See our FAQ on how much space you'll need for more info).

It's important that this part of your roof sees the sun throughout the day, so a north facing roof won't be suitable. We'll also need to be able to install scaffolding below this part of the building in order to complete the installation.

Next, you'll need to decide if solar panels make financial sense. The higher your energy usage at home, the more beneficial solar panels and a battery will be (you'll be saving the money you would have otherwise spent on bills, and this will go towards paying back the cost of your solar system). If you have a low usage, it's worth keeping in mind that your payback period will be longer, but this is something we can discuss in your consultation.

What’s the process to get solar installed?


First up, our solar sales specialists will work with you to plan the perfect solar panel setup for your home, using state-of-the-art software to visualise the path of the sun, and where to best position the panels on your roof.

Next we’ll book a quick home survey to take measurements and discuss where to fit the tech that will accompany your panels. Before the survey we take a £500 fully refundable deposit, and at this point you’ll receive a quote which will include the estimated investment return period.

Once you’re happy, we'll find a suitable installation date. Installation should take 2-4 days, depending on the size of your system. We will also schedule time on either side of this to put up and take down the scaffolding at your property. Once installation is complete, we’ll request the remainder of the total cost.

We’ll be here to answer any questions or concerns that you have throughout the process, and even after the installation is completed.

What is battery storage?


A battery will allow you to store any electricity you don't use, so that instead of exporting the energy back to the grid, you can use it later when the sun isn't shining. The initial cost for a battery is higher than solar panels alone, but it's a great idea if you wish to be self-sufficient and avoid spending money on pricey electricity from the grid in the long-run. You can also guarantee that the majority of the electricity you're using is 100% clean, green and home-generated.

Should I get battery storage installed too?


This depends on both how much electricity you generate and when you use it most. For example, if you tend to use a lot of energy in the evening, we’ll probably recommend a battery. This is because you won’t be there to use the energy when the sun is brightest during the day; instead you can store the electricity in the battery for use in the evening. Our lives are varied, so there are many more circumstances that might impact this decision - but this is something that our solar advisors will be able to help you with.

I already have solar panels, would you install a battery to work with them?


As we're just getting started, we're only installing complete solar systems for now (solar panels alone or with a battery). This means that if you have solar panels fitted by another provider, unfortunately we're not able to install a battery to work with them just yet.

What's the average cost?


The cost of your installation will depend on the number of panels you need and whether you choose to have battery storage. The average cost for a solar panel and battery storage installation is £9,138.

How long will it take for the panels to pay for themselves?


This will depend on a number of different factors including the number of panels, the amount of electricity consumed from the panels and the cost of your electricity bill. As a general rule the more electricity you generate and use yourself, the less you’ll have to buy from the grid and the shorter the payback period. We’ll let you know how long we estimate your investment return will be in your quote.

How do I get paid to export energy?


Once your installation is complete, you’ll start generating electricity straight away, but it will take a couple of weeks before your export MPAN is ready and you can start getting paid for the energy you export. You’ll also need to get a smart meter installed if you don’t have one already, but we can get all of this sorted for you. If you choose to keep your supply with us, you can join one of our Outgoing Octopus tariffs and your export payments will be credited monthly to your Octopus account. Find out more.

What is the best Octopus Energy tariff for solar?


If you're already with Octopus for your energy supply, you can sign up to our Outgoing Octopus, which comes in two flavours – Fixed or Agile. Outgoing Fixed guarantees 15p for every unit you export. Outgoing Agile varies every half hour based on how much green energy there is on the grid. If you're with another supplier for your energy, you can still sign up to our Smart Export Guarantee tariff and earn 4.1p for every kWh you export.Find out more.

Does it matter which direction my roof is facing?


In the UK, south facing solar panels will generate the most energy as they spend the maximum time facing the sun, whereas north facing panels are not recommended because they’ll see little direct sunlight. The Energy Savings Trust estimates that panels facing east or west will yield around 15-20% less energy than one facing directly south. However if you have both an eastern and western facing roof, you have the option to have panels on each side, to follow the sun’s path throughout the day.

It’s also important to avoid shady spots on your roof to generate the maximum amount of energy.

How much space do I need?


On your roof, the number of panels we recommend will depend on the amount of space you have and how much energy you use.

Our panels are 1.7m length 1.1m wide each, and we'll need space for a 40cm gap between the edge of the roof and the solar system. The average number of panels is around 9-10 (3.5kW) and the minimum number we can fit is 6. As an example, 9-10 panels would fit a roof of around 26m2, where the array would take up a total space of around 5.1m x 3.3m.

In general, the more panels on the roof, the more electricity you will generate, so we’d only recommend a large array if your usage is high. We’ll discuss all of these options with you.

Inside your home, you will need space for an inverter measuring: (HxDxW) 440 x 260 x 480 (mm)

If you choose to also have a battery, these come in 2 different sizes:

5.2kWh dimensions: (HxDxW) 515 x 220 x 480 (mm)

9.5kWh dimensions: (HxDxW) 800 x 223 x 480 (mm)

Does it matter what type of roof I have?


A roof where water is able to run off the solar panels will be suitable, but a pitched roof is best, as it can provide the best angle for a solar panel to face the sun, without having to use a stand. Unfortunately we’re not able to install solar panels on flat roofs, thatched roofs or slate roofs just now.

Can I get solar panels if I'm renting?


Unfortunately you need to be the property owner to have Solar panels installed on your roof. Additionally, if you own a top floor flat you may need to get the freeholders permission to have solar installed on the roof.

Do they work when it’s cloudy?


Yes - even when it's cloudy and grey, snowing or raining, the panels will still generate electricity if it’s light outside, although less will be generated than in bright sunshine. The only time the panels won’t generate is at nighttime, because the sun isn’t shining.

What happens if I move house?


Because your solar array will be designed and tailored specifically for your property, we recommend that they stay with the house if you move. This means you can factor them into the price of your home if you choose to sell.

What happens if they break?


We currently offer a 12 year product warranty which will cover the panels if they need any repairs during that time (as long as they haven’t been tampered with), and a 25 year performance warranty (the panels are guaranteed to have 80% output capacity during this time).

How do you maintain them?


One of the best things about solar is that the panels are easy to maintain. Our bird proofing ensures that pigeons aren’t able to nest and tamper with your system, and the angle of the panels ensures that rain and snow will slide right off whilst cleaning them at the same time. Over time, you’ll need to be aware of anything new shading the panels to make sure you continue to get the very best out of them.

What other devices will be installed with my solar panels?


Together with your solar panels, we’ll install:

  • A small consumer unit (also known as a fuse box),
  • An export meter, to measure how much energy your panels generate, and how much of that is exported to the grid.
  • An inverter, to convert the electricity into an alternating current, which can be used to power your home.
  • (Optional) A battery, to store any excess electricity that’s generated.

Where will the rest of the system fit in my home?


Your consumer unit is small and will be placed next to your existing consumer unit/fuse box. The inverter and the battery (if you choose to have one) will usually go in the loft but can go elsewhere if there’s no space there. The physical size of the battery will depend on how powerful it is, but to give you an idea, the smallest battery is around the size of plane carry-on luggage and the larger battery is the size of a check-in bag. The inverter is about the same size as the smallest battery.

Do they make any noise?


The solar panels themselves don’t make any noise, however during the day whilst the panels are generating, your inverter may hum quietly at a maximum of 45 decibels (the sound level of a quiet library).

How long does it take to install and do I have to be there?


Standard installs can be completed within 2-3 days, and bigger installs can take between 3-4 days. If you need to be elsewhere, no problem - we just ask that you’re in the property whilst we do the wiring, which will take a few hours on one day.

Will there be any damage to my property or roof?


Our install team will take proper care to ensure your property is left in a good condition and undamaged. If a roof tile does crack, we will be sure to replace it, whether with a spare or a new tile. If your property is suitable and you opt for our self-mountable scaffold solution, Easi-Dec, we will need to drill in one fixing point into your wall to secure it. We will remove this after installation and re-fill any holes made.

Do I need planning permission?


The only time you will need planning permission to install Solar Panels is when the property is listed or in a conservation area. In cases where your system will require a 5kWh inverter (usually around 12 panels or more), we’ll need to get in touch with your distribution network operator (DNO) to ask for permission. This process usually takes a couple of weeks but we will sort everything for you.

What models do you use?


We’re currently using a range of leading solar and battery providers, all of which have been vetted by Octopus for delivering good quality at a low cost. Get in touch to find out more.

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