E.ON Next home battery: prices, finance and the small print

E.ON Next battery prices against the official medians

E.ON Next fits two batteries and publishes one starting price for each. Dividing by usable capacity makes them comparable with each other and with the official DESNZ medians, which cover every MCS-certified battery fitted in an existing home between April 2025 and March 2026:

Both are below the median for their size, and the pattern matches every other supplier: the bigger battery costs far less per kWh, because the survey, labour and grid connection cost much the same for any size. The “from” prices are E.ON’s published starting prices, so the quote for your home may differ after the survey. The page does not say whether the prices include VAT, and it does not mention the 0% rate, so check that your written quote shows no VAT on the installed battery.

How E.ON compares with Octopus and EDF

Three suppliers publish a price for the same Tesla unit:

E.ON is £200 below EDF and £204 below Octopus on the Powerwall. At the small end the comparison reverses: Octopus fits a 5 kWh battery with 5.0 kWh usable at £3,947 (about £789 per usable kWh), which is £48 less than E.ON’s Sunsynk and gives 0.4 kWh more usable capacity. The Octopus home battery guide sets out its range and conditions in the same format.

Because the three Powerwall prices sit within 3% of each other, the supplier you choose for the Tesla should depend on the rest of the offer: the finance, the tariff it comes with and who stands behind the installation, not on a few hundred pounds. An independent installer can quote the same unit, and a quote checklist shows what to compare.

Finance and discount codes

E.ON’s buy page lists two ways to spread the cost:

• 0% APR for up to 3 years. The remaining cost is split over up to 36 months, subject to status, affordability and a credit check. The credit is provided by HomeServe Finance Limited.
• 7.9% APR over 5 or 10 years. The representative example on the page is a £3,995 order with a £998.75 deposit, paid over 120 months at £35.77, with £5,291.15 payable in total.

The arithmetic on the example is worth doing before you sign. 120 payments of £35.77 is £4,292.40, and with the £998.75 deposit that totals £5,291.15, which is £1,296.15 more than the £3,995 price. The page states a cost of finance of £2,294.90, which is the interest plus the deposit rather than the interest alone, and the page does not explain the difference, so ask the lender for the interest figure in writing. The 0% option is the cheaper route on any battery you can clear within 36 months; the longer loans are a good deal only if the interest is lower than what you would earn on the cash.

The two discount codes on the page, SOLAR200 (£200 off solar and battery together) and SOLAR150 (£150 off a battery alone), are for existing E.ON customers only. The earlier promotion, £1,000 off batteries of 13 kWh or more and £500 off 10 to 12 kWh, applied to battery-only orders as well as solar packages and ended at 5pm on 24 September 2026. If you see a discount advertised later, ask for the end date.

What the battery saves

This site’s model, for a London home using 3,000 kWh a year, with E.ON’s published prices:

The first two rows are the saving on a standard flat tariff and they explain why E.ON’s battery is not a good fit by itself: on a flat tariff the battery only stores your own spare solar, and a bigger battery has nothing more to store. The saving comes from the tariff. Flux, Go and Agile are Octopus tariffs, so a Powerwall paid for through E.ON earns most if you also move your electricity to a time-of-use tariff, from E.ON or from Octopus. E.ON’s page points to its own smart tariff arrangements for import customers and mentions a trial with Northern Powergrid in which households saved “almost £500 a year”; that is E.ON’s claim about a trial, not a figure from this site’s model. The best tariff for a home battery page compares what each tariff pays, and the calculator lets you test your own usage.

Sizing: take E.ON’s table with care

E.ON’s September promotion page includes a sizing guide: a 1 to 2 bedroom home using 4 to 6 kWh a day needs 5 to 7 kWh; a 3 to 4 bedroom family home using 7 to 12 kWh a day needs 10 to 13.5 kWh; a large home or one with an electric car, 10 to 20 kWh or more. Two of those steps point to the products E.ON sells, and a bigger battery is not automatically a better buy. In this site’s model, the saving from extra capacity levels off once the battery covers your evening use, and the what size battery guide shows where. The 10 kWh and 13kWh pages price those sizes across brands.

The small print worth a question

• Warranty. E.ON lists 10 years from the manufacturer for both batteries, plus a 2-year workmanship warranty. Ask who answers a claim in year 5, and what happens if the installer or the manufacturer stops trading; the GivEnergy administration shows why.
• Installation. E.ON says a few hours, with the power off briefly, and an MCS-certified installation. Ask for the MCS certificate number.
• Network notification. Your installer notifies your network operator, or applies in advance if the combined inverters exceed 3.68 kW; the G99 guide explains the line.
• Existing solar. If you already have panels, check that the battery is compatible with your inverter; the retrofit guide covers AC and DC coupling.
• VAT. The page is silent. Installed batteries are zero-rated until 31 March 2027, so a quote that adds VAT should be queried.

Getting a price to compare

E.ON’s two prices are a useful benchmark for a quote from anyone else. Put its price for your size next to quotes from an MCS-certified installer, divide each by usable kWh, and check the result against the medians above. Send a battery storage quotes request if you would like a reply by email, and run any written quote through the quote checker before you pay a deposit. This site does not install batteries and is not affiliated with E.ON.