Solar battery storage
Is a solar battery worth it in the UK?
Short answer: it depends on your usage pattern more than your roof. Long answer below — plus real UK 2026 cost ranges and a calculator that compares battery vs no-battery for your home.
Check your roof
A Solarable Report shows your likely roof direction, a Solarable Score, and listed installers covering your postcode.
The honest verdict
When a battery is worth it, and when it isn't.
A solar battery stores electricity your panels generate during the day so you can use it in the evening, instead of selling it back to the grid for a low export tariff. The maths is straightforward — but the answer changes a lot depending on how you actually use electricity.
Worth it when:
- Most of your electricity use is in the evening (after solar generation drops).
- You have a time-of-use tariff with a cheap overnight rate — a battery can charge from the grid overnight and discharge during peak rates the next day.
- You have a larger solar system (5+ kWp) generating more than you use during the day.
- You want backup power for occasional grid outages.
Less worth it when:
- You're home and using lots of electricity during the day (washing, cooking, EV charging).
- Your solar system is small (2-3 kWp) — there's not much daily surplus to store.
- You have a fixed-rate tariff with no overnight cheap window.
- Budget is tight and the £3,000-£6,000 battery cost extends your payback.
Real numbers
What a battery actually costs in 2026.
Battery prices have come down meaningfully since 2022 but vary widely by brand. As a UK domestic ballpark in 2026:
- 5kWh battery installed alongside new solar: £3,000–£4,500. Cheaper because the installer is already on site and the inverter is being chosen with battery integration in mind.
- 5kWh battery retrofitted to existing solar: £3,500–£5,500. Modest premium for the standalone install.
- 10kWh battery (Tesla Powerwall, larger GivEnergy, etc.): £5,500–£8,000. Brand and capacity premium.
- VAT: Currently 0% on residential battery storage installed alongside solar (running through 2027 under current UK policy).
These are installed prices — including the battery, any required inverter adjustment, and labour. Hardware-only prices online look cheaper, but you'll need an installer for safety, certification, and SEG eligibility.
Use the calculator
See the difference for your home.
The savings calculator includes a battery toggle. Turn it on to see how a battery changes your annual benefit and payback range — versus the same setup without one. Both numbers come back as honest ranges, not single figures.
Common questions
FAQs.
Is a solar battery worth it in the UK?
Sometimes — and the answer is more sensitive to your usage pattern than to your roof. If most of your electricity use is in the evening (after generation has dropped), a battery captures the daytime surplus and uses it later. If you're home and using a lot of electricity during the day, a battery has less to do. The savings calculator estimates both scenarios so you can see which fits your home.
How much does a solar battery cost installed in 2026?
A typical 5-7kWh domestic battery installation costs around £3,000–£6,000 in the UK in 2026. The range depends on size, brand, whether it's being installed alongside new solar (cheaper, shared install costs) or retrofitted to an existing system (slightly more), and the inverter setup. Brand premium also varies — Tesla Powerwall sits at the top end, GivEnergy and similar at the bottom.
Can I add a battery to my existing solar system later?
Yes. Adding a battery to an existing solar PV system is common — most modern inverters either support battery integration directly or pair with a separate battery inverter. Your installer will check your existing inverter and recommend a compatible setup. Retrofit costs slightly more than installing battery + solar at the same time.
What size battery do I need?
Most UK homes land on a 5-10kWh battery. The sweet spot is usually around 1-2kWh per kWp of solar — so a 4 kWp system pairs well with a 5kWh battery, and a 7 kWp system with a 7-10kWh one. Bigger isn't always better: a battery you can't fill with daily generation is wasted capacity.
How long do solar batteries last?
Most domestic lithium-ion batteries are warranted for 10 years and rated for around 6,000-10,000 cycles. In typical UK use that's roughly one cycle per day, so the warranty period is the limiting factor. Capacity degrades gently over time — most batteries are still at 70-80% of original capacity at year 10.
Does a battery let me go off-grid?
No — not at typical domestic battery sizes. Going off-grid in the UK requires a much larger battery system, a backup generator, and significant infrastructure. A standard solar + battery setup keeps you grid-connected; the battery just shifts when you use your own generation. Some systems can do "backup" — keeping a few essential circuits running during a power cut — which is different from off-grid.
Related
Keep going.
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