Home battery payback
20 kWh home battery payback example
This worked example shows how simple payback changes with installed cost, cycling, round-trip efficiency and the value of each shifted kWh.
Illustrative base case9.6 years simple payback
£9,500 installed cost · 0.75 cycles/day · 90% efficiency · 20p/kWh value spread
Low / base / high-benefit sensitivity
| Scenario | Cost | Cycles | Efficiency | Spread | Useful shifted energy | Annual value | Payback |
|---|---|---|---|---|---|---|---|
| Cautious | £11,400 | 0.50/day | 88% | 12p | 3,212 kWh | £385/yr | 29.6 yrs |
| Base | £9,500 | 0.75/day | 90% | 20p | 4,928 kWh | £986/yr | 9.6 yrs |
| High-use / wide spread | £8,075 | 0.90/day | 92% | 28p | 6,044 kWh | £1,692/yr | 4.8 yrs |
The installed cost is a worked-example assumption, not a current quote. Battery degradation, usable capacity, warranty limits, financing, export effects and real control behaviour are excluded from simple payback.