What does a solar battery do?
A solar battery stores the surplus electricity your panels generate during the day so you can use it in the evening and overnight, rather than exporting it to the grid. This means you use more of the electricity your panels produce and buy less from the grid during peak hours when it is more expensive. The battery is connected to your solar system and charges automatically when there is surplus generation.
Battery capacity is measured in kilowatt-hours (kWh). A 5 kWh battery stores enough to run a typical household's evening usage for several hours. A 10 kWh battery stores more and is suitable for larger homes or households with higher evening consumption. The survey recommends an appropriate size based on your generation and usage.
Why is a battery particularly useful in Scotland?
Scotland has a marked contrast between long summer days and short winter days. In summer, your panels may generate well for 16 or more hours and produce more than you use. In winter, generation is lower and you need more grid electricity in the long, dark evenings. A battery helps bridge this: it stores surplus summer generation for the evening, and on winter days it can store whatever generation there is for when you need it most.
If you are out during the day and use most of your electricity in the evening, a battery makes a significant difference to how much of your solar generation you actually use. Without a battery, most of your daytime generation is exported. With a battery, you keep it and use it yourself.
How much does a battery cost?
Indicative battery costs installed at 0% VAT in October 2026 are:
| Battery | Indicative range (installed, 0% VAT) |
|---|---|
| 5 kWh battery | £3,500–£4,500 |
| 10 kWh battery | £5,500–£7,000 |
Figures are indicative ranges for October 2026 at 0% VAT (ends 31 March 2027). Actual quotes vary by property. Interest-free credit up to £30,000, subject to status.
See our full cost guide for combined solar and battery pricing, and our finance page for paying monthly with interest-free credit.
Can I add a battery to my existing solar panels?
Yes. If you already have solar panels, you can add a battery storage system. The survey assesses your current setup, checks your inverter compatibility, and recommends a battery that works with your existing array. In some cases, the inverter may need to be changed or supplemented to accommodate battery storage — this is assessed during the survey and included in your quote.
Should I choose solar and battery together or separately?
If you are installing solar for the first time, adding a battery at the same time is generally more cost-effective than adding one later, because the installation is done in a single visit and the system is designed to work together from the start. However, if budget is a concern, you can start with panels only and add a battery later. The survey discusses both options so you can decide what suits your situation. See our How It Works page for the full process.
For everything on home battery systems, see our sister site Battery Storage Scotland. For more answers, visit Scottish Energy Efficiency questions.
Frequently asked questions
Can I add a battery to existing solar panels?
Yes. If you already have solar panels installed, you can add a battery storage system. The survey assesses your current setup, inverter compatibility and your usage patterns to recommend an appropriate battery capacity.
How long does a solar battery last?
Solar battery lifespan varies by manufacturer and usage but is typically 10-15 years. Most batteries come with a manufacturer warranty. The survey includes a discussion of warranty terms for the recommended equipment.
What size battery do I need?
The right battery capacity depends on how much surplus your solar panels generate and how much electricity you use in the evening and overnight. A 5 kWh battery suits smaller households, while a 10 kWh battery is better for larger homes or higher evening usage. The survey recommends an appropriate size.
Does 0% VAT apply to battery storage?
Yes. 0% VAT on the supply and installation of qualifying battery storage runs until 31 March 2027, whether you install a battery alongside new solar panels or add one to an existing system.
Can I get a battery without solar panels?
Yes. You can request a quote for battery storage only. A battery can store electricity from the grid during cheaper off-peak periods for use during peak times, depending on your electricity tariff. The survey discusses whether this is suitable for your setup.
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Last updated: October 2026 · Reviewed by the Scottish Energy Efficiency team