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Batteries · Advice

Should I wait for battery prices to fall?

Short answer

Cell prices have already fallen sharply - BloombergNEF found stationary storage packs dropped about 45% in 2025 to around $70/kWh - but installation, inverters and labour make up much of a UK quote. Waiting a year may save a little; it costs a year of savings, and 0% VAT on batteries is due to end on 31 March 2027.

Last checked 24 September 2026 · 6 sources

What should I know before deciding?

Compare: annual saving (e.g. £400-700) vs expected price fall on the installed quote. Sodium-ion is arriving but costs more per kWh today. Buying modular LFP now and expanding later is a middle path (check expansion rules).

How much does a home battery cost per kWh in 2026?

Official MCS data for 2025/26 put the median installed cost at £1,300 per kWh for batteries under 6 kWh, £890 for 6–11 kWh and £630 for 11–30 kWh. That's roughly £6,700, £8,700 and £9,750 for typical systems. Big suppliers advertise less: Octopus fits 10 kWh from £5,336 and a Powerwall 3 from £7,999.

DESNZ figures are per NOMINAL kWh and include installation, grid connection and VAT, but not solar or extended warranties. They cover existing homes, MCS-registered only. Costs rose for small systems (1-5.99 kWh median £1,080 → £1,300) and eased for large (590 → 630, 910 → 890) between 2024/25 and 2025/26. Model cost as a fixed install element (~£1,200-£1,750) plus hardware £/kWh. Expansion modules cost ~£350-£520 per kWh (Sigen module prices).

How long does a home battery take to pay back, according to published analyses?

Published figures vary widely. Nesta's January 2026 modelling credits a 5 kWh battery with only £54–£128 a year on top of solar, which means decades at typical prices. Large batteries on wide-spread EV tariffs can save £1,000–£1,600 a year and pay back in about 7–10 years. Which? warns the battery may need replacing once over solar's 25-year life.

Nesta (20 Jan 2026, April 2026 prices, 2-3 bed home, 3,740 kWh solar, 5 kWh battery): solar only £1,047/yr vs solar + battery £919 (ToU); heat pump + solar £721 vs + battery £667. Implied battery increment £128/yr and £54/yr. At DESNZ 1-5.99 kWh median (~£6,700) that's 50+ year payback; at Octopus 5 kWh £3,947, ~31 years (derived). Worked example here (24 kWh/day, IOG, 23 kWh usable): ~£1,635/yr vs ~£13,100 → ~8 years (derived).

What to do next

Use your own half-hourly electricity data where possible. Compare usable kWh, kW, tariff rules and warranty terms before buying.

Sources

Last checked: 24 September 2026