How the battery prices on this site are worked out
Every price on this site comes from one official dataset and one stated method. This page sets out both, including the places where the data runs out and we have had to make a choice.
Quick answer
We take DESNZ's 2025/26 medians for home batteries registered with MCS (£1,300, £890 and £630 per nominal kWh by size band), place each median at its band's average battery size, join the points with straight lines, and round the result to £100. From 1 April 2027 we multiply by 1.05 for 5% VAT. We show no range, because DESNZ publishes none.
The data
The Department for Energy Security and Net Zero publishes "MCS certified domestic battery installation statistics" as official statistics in development. The workbook we use covers April 2024 to March 2026 and was published on 28 May 2026; we re-read it on 3 November 2026. It counts batteries registered on the MCS database and classed as installed in existing homes. New-build and commercial installations are not included, and nor are batteries that were never registered with MCS.
For each financial year and each of three size bands, DESNZ gives the number of batteries in its sample, their total capacity, and the mean and median cost per kWh. The cost covers the battery, installing it and connecting it to the supply, and VAT where it applied. It excludes extended warranties, other materials or works, and additional devices such as solar panels. The figures are not adjusted for inflation and may be revised. Before calculating, DESNZ removes batteries under 1 kWh or over 30 kWh and costs under £100 or over £5,000 per unit of capacity, and rounds costs and capacities to the nearest 10.
| Band | Batteries | Total kWh | Average size* | Median £/kWh | Mean £/kWh |
|---|---|---|---|---|---|
| 1 to 5.99 kWh | 16,270 | 83,560 | 5.14 | £1,300 | £1,280 |
| 6 to 10.99 kWh | 14,457 | 141,650 | 9.80 | £890 | £870 |
| 11 to 29.99 kWh | 12,176 | 188,540 | 15.48 | £630 | £670 |
The batteries in the price sample are slightly fewer than the batteries recorded: the monthly sheet gives 44,033 recorded in 2025/26 and 24,242 in 2024/25, before outliers are removed.
The price curve
Multiplying a size by its band median is the obvious method and the wrong one at the edges. It makes a 10.9 kWh battery about £9,700 and an 11 kWh battery about £6,900: a price that falls by thousands as the battery gets bigger.
Instead we treat each median as the price per kWh of a band's typical battery, placed at the band's average size. That gives three anchor points: 5.14 kWh at £6,677; 9.80 kWh at £8,720; 15.48 kWh at £9,755. Between anchors we join the points with straight lines. Below the first anchor we use size times £1,300; above the last, size times £630. The result never falls as size rises.
Checks the maths has to pass
The same code produces the figures you read on the page and the ones the calculator shows as you move the slider, so they can't drift apart. Before every build it is tested against fixed values, including these:
| Nominal size | Modelled price | Size × band median |
|---|---|---|
| 5 kWh | £6,500 | £6,500 |
| 10 kWh | £8,757 | £8,900 |
| 10.9 kWh | £8,921 | £9,701 |
| 11 kWh | £8,939 | £6,930 |
| 15 kWh | £9,667 | £9,450 |
| 20 kWh | £12,600 | £12,600 |
Rounding, VAT and what we never do
- Rounding. Prices shown as "about" are rounded to the nearest £100, after any VAT step. Per-kWh figures are rounded to the pound.
- VAT. DESNZ's 2025/26 costs were recorded while installed home batteries were zero-rated, so we treat them as 0% VAT prices. From 1 April 2027, HMRC Notice 708/6 sets 5%; we multiply the same pre-VAT price by 1.05. When we check a quote dated after that, we divide by 1.05 first.
- No range. DESNZ publishes medians and means, not a spread. We don't invent one.
- No other prices. We don't use energy suppliers' or installers' advertised prices, because what they include is unknown. Which? appears only as a marked secondary source.
- No headline savings. A year-one bill figure appears only when you enter your own tariff, with the share of solar a home uses itself capped at 75% without a battery and 90% with one. We never show payback periods or lifetime totals.
Limits you should know
A median says nothing about how far quotes spread either side of it. The data covers batteries registered with MCS only. The bands are wide, so the curve is our assumption between three points, not a measured price for every size. The figures are a year old by the time most people read them, and DESNZ may revise them. When the next release comes, usually in late May, we re-pull the workbook and update every price on the site.
Found an error, or a source we should read? Tell us through the contact page. More about who publishes this site is on about, and the calculator uses everything on this page.
Sources (page last reviewed 3 November 2026)
- DESNZ: MCS certified domestic battery installation statistics (April 2024 to March 2026 workbook, published 28 May 2026), checked 3 November 2026.
- HMRC: VAT on energy-saving materials and heating equipment (Notice 708/6), sections 2.1, 2.3 and 2.19, checked 3 November 2026.
- Which?: solar panel battery storage (secondary source, page updated 30 October 2026), checked 3 November 2026.
Want quotes to hold up against these figures?
Tell us the battery size you are pricing and your postcode. Your enquiry reaches SEO-DONS LTD, the company that publishes this price guide, and we reply by email. Sending it costs you nothing and commits you to nothing.
What happens next
- SEO-DONS LTD, the publisher of this price guide, receives your enquiry.
- We read what you sent and answer by email.
- You decide what, if anything, happens next.