Battery only
Solar already on the roof
5 kWh battery, existing 4 kWp solar
Installed, 0% VAT£2,750 to £4,750
Saves a year£90 to £130
Payback25 to 43 years
Prices checked October 2026
Battery only in Faversham: retrofit or cheap-rate
A battery without new panels. Add it to solar you already have, or fill it from cheap overnight power. 0% VAT covers a battery installed on its own until 31 March 2027.
Worked examples
What it costs for a Faversham house
Battery only
Solar already, high evening use
10 kWh battery, existing 4 kWp solar
Installed, 0% VAT£5,000 to £8,750
Saves a year£180 to £270
Payback23 to 40 years
Battery only
Solar plus a cheap overnight rate
5 kWh battery, existing 4 kWp solar
Installed, 0% VAT£2,750 to £4,750
Saves a year£180 to £280
Payback12 to 21 years
Battery only
No solar, smart tariff
5 kWh battery, no solar
Installed, 0% VAT£2,750 to £4,750
Saves a year£180 to £270
Payback12 to 21 years
Estimates, not quotes. Prices assume 0% VAT (ends 31 March 2027, then 5%). Bar length is payback against a 45 year scale: a longer bar means a longer wait, and a battery lasts about 10 to 12 years. Plug-in solar figures are Energy Saving Trust, October 2026. See the notes under the full table on the costs page.
Who it suits
- You already have solar and export a lot
- You are on a cheap overnight or time-of-use tariff
- You have an electric car or a heat pump
- You would rather use power later than sell it for a low rate
How it works
- You tell us about your solar, your meter and your tariff.
- We check your inverter and fuse board, and where a battery can go.
- You get a clear quote and a straight view on payback.
- Our MCS-certified installation partner fits it, usually in one day.
- The network operator is notified and the battery is set up for your tariff.
Local notes for Faversham
Added to existing solar
Many houses had solar fitted years ago. Older inverters may not suit a new battery. We check first, so you do not pay twice.
Standalone on a cheap rate
A smart tariff lets you fill overnight and use the power in the evening. In the South East on 7 October 2026 Octopus lists Intelligent Octopus Go on a 12-month fixed deal at 7.6p per kWh at night, Octopus Go 12-month fixed at 9.5p, and Cosy at about 12.6p for its cheap periods. Check your own tariff and its exit terms.
Be realistic
A battery alone saves less than solar does. Our model gives £90 to £130 a year for 5 kWh on existing solar, and the Energy Saving Trust says savings will not always justify the cost on their own. We run the numbers with you before you spend anything.
0% VAT, even alone
Since 1 February 2024 a battery installed on its own in a home gets 0% VAT too, until 31 March 2027 (GOV.UK VAT Notice 708/6).
A route for flats
A battery needs no roof, so it can suit a flat where roof panels are not possible. A battery inside a flat needs the landlord's or freeholder's permission, and we cover the checks on the plug-in solar page.
Questions about this
How much does a battery cost?
As of October 2026, about £2,750 to £4,750 for 5 kWh and £5,000 to £8,750 for 10 kWh. The Energy Saving Trust gives about £4,600 for 5 kWh within a range of £1,500 to £10,000.
How long does a battery last?
About 10 to 12 years, says the Energy Saving Trust. Ask about the warranty.
Can I fit a battery without solar?
Yes. It then only saves money if you fill it at a cheap rate and use it at a dear one, so you need a smart meter and a suitable tariff.
Does the battery lose power?
Yes. Using stored power is less efficient than using it straight away. We assume about 10% is lost.
Last reviewed 7 October 2026. Estimates only, not quotes. 0% VAT applies until 31 March 2027, then 5%.
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