Home battery guides and articles
Everything here is written to help you make one decision well: whether to buy a battery, which one, how big, on which tariff and from whom. Each page lists its sources and the date its facts were last checked.
Prices and rules checked 27 September 2026
Three questions to answer first
Whether a battery pays for your home, what size it should be, and how to tell a fair quote from a poor one. Most of the rest of the site builds on these.
A suggested order, depending on where you are. Still deciding: read whether a battery is worth it, then the myths guide, then the tariff guide, because the tariff you can join decides most of the saving. Already have solar panels: start with sizing, then AC versus DC coupling, since the answer decides whether your existing inverter stays. Holding a quote: go straight to the comparison checklist and the installer guide, and put the price through the calculator before you sign anything.
Is a home battery worth it?
Modelled savings and payback by tariff, with and without solar, the prices that make a battery pay, and when it does not.
Updated 28 September 2026 →GuideWhat size battery do I need?
Size to the hours your panels do not cover: modelled savings by household use and tariff, and when bigger pays.
Updated 6 October 2026 →GuideHow to compare quotes
The line-by-line method: usable kWh, price per kWh against the official median, the items that should be listed and the savings claim.
Updated 28 September 2026 →Guides to the rules, the kit and the people
The fire-safety specification that decides where a battery can go, how batteries connect to solar, which tariffs pay a battery best, how long they last and how to check an installer.
Choosing an installer
The registers to check, what a proper installation includes, deposit rules and the red flags in a sales visit.
Updated 27 September 2026 →PAS 63100 explained
Where a battery can and cannot go room by room, the fire-separation, alarm and capacity rules, and the certificate to ask for.
Updated 14 October 2026 →Best tariff for a battery
Flux, Agile, Go and Cosy compared on eligibility and rates, with every region's Flux prices and the export options.
Updated 28 October 2026 →How long batteries last
Warranty terms decoded, cycle ratings, measured real-world fade, what shortens a battery's life and what happens at the end.
Updated 27 September 2026 →AC vs DC coupled
How AC and DC coupling connect a battery, efficiency and cost differences, and which suits a retrofit or a new system.
Updated 14 October 2026 →Home battery myths
Ten claims from sales pitches checked against the evidence, from power cuts and payback to grants and VAT.
Updated 27 September 2026 →Octopus home battery
Octopus's battery prices, packages, deposit and tariff rules, checked against the official medians.
Updated 28 October 2026 →G98 and G99 explained
G98 or G99, the three fast-track categories, response times, and the rules of all 14 network areas and Northern Ireland.
Updated 7 October 2026 →E.ON Next battery
E.ON Next's two batteries, prices per kWh against the official medians, finance terms and what each saves.
Updated 18 October 2026 →Duracell battery
Who makes Duracell home batteries, the Dura5 and Dura16 specs and hardware prices, and what to ask about the warranty.
Updated 20 October 2026 →Octopus Flux rates
Every region's Flux import and export rates, the 19 October standing charge rise, who can join and what the rate gap is worth.
Updated 28 October 2026 →Plug-in solar batteries
What the 2026 plug-in solar regulations cover, why batteries are excluded, the DESNZ safety study to 2028 and the installed alternative.
Updated 7 October 2026 →Octopus export tariffs
Octopus's five export tariffs side by side, what Agile Outgoing paid by region over 12 months, the Prime break-even and who should choose which.
Updated 28 October 2026 →Solar panels and battery cost
Supplier package prices, the official cost per kW and per kWh, what buying together saves and how long each part takes to repay.
Updated 7 October 2026 →Sunsynk battery
The Sunsynk Elite module, prices from E.ON and EDF, the warranty conflicts between product lines and who stands behind it.
Updated 20 October 2026 →Supplier batteries compared
Octopus, E.ON Next, EDF and British Gas home batteries: prices, finance, warranties and what each ties you to.
Updated 20 October 2026 →Best solar battery
One pick per situation: new solar, existing solar, 10 kWh value, small budget, no solar, with prices per kWh and warranty terms.
Updated 20 October 2026 →Solar battery sizes
All the common sizes in one table: capacity, how it is built, price, and what it saves.
Updated 18 October 2026 →Northern Ireland
NIE Networks' G98/NI and G99/NI rules, export without the SEG, Power NI's day and night rates, solar yield from Belfast to Enniskillen and the funding that does and does not exist.
Updated 3 November 2026 →Brands, comparisons and what has changed
What Happened to GivEnergy? The Administration Explained
The April 2026 administration, what has changed since, warranties, the app, and practical steps for owners.
Updated 28 October 2026 →AnalysisHow long do UK power cuts last, and how much battery does that take?
Average length of UK power cuts by network from Ofgem's data, planned against unplanned, what storms add and the battery size each case needs.
Updated 14 October 2026 →AnalysisBS 7671 Amendment 4 and home batteries: what changes on 15 October 2026
The new batteries chapter in the Wiring Regulations, the PAS 63100 link, the RCD rule and the 15 October 2026 date.
Updated 14 October 2026 →AnalysisWhat would a 10kWh battery have earned on Agile over the last 12 months?
A day-by-day back-test of a battery on 12 months of real Agile prices: savings by region, the daily range, negative prices and why size barely mattered.
Updated 14 October 2026 →AnalysisHow much of a Fox EVO installation is hardware, and how much is everything else?
Five retailer listings for the EVO 10 against Octopus's installed price: what is hardware, what is installation, and how VAT changes the comparison.
Updated 7 October 2026 →AnalysisWhat does each kWh a home battery delivers really cost?
Price divided by the kWh a battery actually delivers over ten years, for three sizes, with and without solar.
Updated 7 October 2026 →AnalysisHow long does a 13.5kWh battery last? Run-times for real loads
Run-times for a 13.5 kWh battery at each power draw, days of typical use, and recharge times from solar by month.
Updated 7 October 2026 →AnalysisHow long does a Powerwall 3 take to pay back? 14 regions modelled
Savings and simple payback for a 13.5 kWh Powerwall 3 in all 14 electricity regions, on Flux with solar and on Go without.
Updated 7 October 2026 →GuideWill adding a battery affect my Feed-in Tariff payments?
What Ofgem's co-location guidance means for a battery added to Feed-in Tariff solar, scenario by scenario, and how Octopus Flux treats it.
Updated 7 October 2026 →ExplainerHow much is the Warm Homes: Local Grant worth? What the £16,600 cap means
The twin £16,600 caps, who pays for what, which measures count towards each, and why a battery is only ever part of a package.
Updated 7 October 2026 →AnalysisDoes a bigger home battery save more?
What the second 5 kWh adds on each tariff, what it costs, and the homes where it adds nothing.
Updated 6 October 2026 →GuideHow long does a home battery take, from quote to switch-on?
Survey, deposit, network approval, installation day and paperwork: what happens when, and what can hold it up.
Updated 6 October 2026 →GuideIs 5kWh enough for a house?
Ofgem's 2026 typical homes against 5 kWh of storage, summer and winter, and the tariffs where it falls short.
Updated 6 October 2026 →ComparisonBest Home Battery UK 2026: Tesla vs Fox ESS vs Sunsynk
Tesla Powerwall 3, Fox ESS and Sunsynk compared on usable kWh, warranty conditions, published prices and fit.
Updated 27 September 2026 →Where the detail lives
- Systems and sizes: solar with a battery, adding one to existing panels, a battery with no solar, backup, and 5 to 20 kWh.
- Brands: Tesla Powerwall 3, Fox ESS and Enphase side by side.
- Regions: tariff rates, solar yield, network operator and power-cut record for every part of Great Britain.
- Cost and grants, VAT and funding: the official prices and what help exists.
- FAQs: short answers, each linking to the page with the detail.
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