Worked examples

Home battery payback examples

Compare 3–20 kWh home battery scenarios. Each page exposes installed cost, cycling, efficiency and tariff-spread assumptions rather than promising a fixed payback.

All worked examples

3 kWh home batteryIllustrative base: £3,550 cost · 24.0-year simple payback at 0.75 cycles/day and 20p/kWh spread

4 kWh home batteryIllustrative base: £3,900 cost · 19.8-year simple payback at 0.75 cycles/day and 20p/kWh spread

5 kWh home batteryIllustrative base: £4,250 cost · 17.3-year simple payback at 0.75 cycles/day and 20p/kWh spread

6 kWh home batteryIllustrative base: £4,600 cost · 15.6-year simple payback at 0.75 cycles/day and 20p/kWh spread

7.5 kWh home batteryIllustrative base: £5,125 cost · 13.9-year simple payback at 0.75 cycles/day and 20p/kWh spread

8 kWh home batteryIllustrative base: £5,300 cost · 13.4-year simple payback at 0.75 cycles/day and 20p/kWh spread

10 kWh home batteryIllustrative base: £6,000 cost · 12.2-year simple payback at 0.75 cycles/day and 20p/kWh spread

12 kWh home batteryIllustrative base: £6,700 cost · 11.3-year simple payback at 0.75 cycles/day and 20p/kWh spread

15 kWh home batteryIllustrative base: £7,750 cost · 10.5-year simple payback at 0.75 cycles/day and 20p/kWh spread

20 kWh home batteryIllustrative base: £9,500 cost · 9.6-year simple payback at 0.75 cycles/day and 20p/kWh spread

Open the home battery payback calculator

What the battery-size range actually shows

The scenarios above are a sensitivity range rather than a recommendation to buy a particular capacity. A larger battery can store more energy, but extra capacity only creates value when the household has enough low-cost or surplus energy to charge it and enough later demand to discharge it. An oversized battery that regularly finishes the day partly charged or partly unused can have a weaker return than a smaller unit that cycles more consistently.

Simple payback is driven by installed cost, usable capacity, round-trip efficiency, the number of useful cycles and the value of each shifted kWh. Solar charging and off-peak tariff charging can produce very different economics, so the same battery can look attractive in one household and poor in another.

Use household data before buying

Check at least several weeks of import, export and time-of-use data where available. The calculator lets you replace the illustrative cost, cycling and tariff-spread assumptions with your own figures. It is also worth testing a lower cycling case: winter and summer behaviour can differ, and a headline battery capacity is not the same as usable energy.

Inputs on these pages are illustrative. Replace them with your own tariff, product, quote or household figures in the linked calculator before making a decision.