What Size Solar Battery Do I Need?
Quick Answer
5–10kWh for a typical home
Match to daily usage minus daytime solar self-consumption. Covers evening/overnight demand.
How to Size a Battery
The ideal battery size depends on:
- Daily electricity usage: Average UK home uses ~10kWh/day
- Daytime self-consumption: ~30–50% of solar is used directly
- Evening/overnight usage: Typically 4–7kWh
- Battery should cover this evening demand
Recommended Sizes by Household
- Small household (1–2 people): 3.5–5kWh
- Medium household (3–4 people): 5–8kWh
- Large household (5+ people): 8–13kWh
- With EV charging: 10–15kWh+
Popular Battery Options (2026)
- Tesla Powerwall 2 (13.5kWh): £8,000–10,000 installed
- GivEnergy 5.2kWh: £2,500–3,500 installed
- GivEnergy 9.5kWh: £4,000–5,500 installed
- Huawei LUNA 2000 (5–15kWh): £3,000–7,000 installed
- SolarEdge Home Battery (10kWh): £5,000–7,000 installed
Is a Battery Worth It?
A battery increases solar self-consumption from ~30–50% to ~70–80%. At current electricity prices (~28p/kWh), a 5kWh battery saving 4kWh/day returns ~£400/year. Payback: 7–10 years.
Time-of-use tariffs (e.g. Octopus Agile) can improve payback significantly by charging from the grid at low rates and discharging at peak rates.
Last updated: April 2026