Home battery payback
What might a 5 kWh home battery payback look like?
A battery's simple payback depends on installed cost, usable cycling and the price difference between charging and avoided peak electricity.
Base worked example16.2 years simple payback
£4,000 installed cost · 0.75 cycles/day · 90% efficiency · 20p/kWh spread
Low / base / high-benefit assumptions
| Scenario | Installed cost | Cycles | Efficiency | Tariff spread | Useful energy | Annual saving | Simple payback |
|---|---|---|---|---|---|---|---|
| Cautious | £4,800 | 0.50/day | 88% | 12p/kWh | 803 kWh/yr | £96/yr | 49.8 yrs |
| Base | £4,000 | 0.75/day | 90% | 20p/kWh | 1,232 kWh/yr | £246/yr | 16.2 yrs |
| High-use / wide spread | £3,200 | 0.90/day | 92% | 28p/kWh | 1,511 kWh/yr | £423/yr | 7.6 yrs |
What the calculation is doing
Useful shifted energy = battery capacity × equivalent cycles/day × 365 × efficiency. Annual gross saving = useful shifted energy × tariff spread. Simple payback = installed cost ÷ annual saving.
The installed costs and tariff spreads are illustrative, not market quotes or current tariff claims. Degradation, financing, replacement, export effects and warranty constraints can materially change the real result.