Cost and whether it pays

Is a battery worth it?

Short answer

A battery may be worthwhile when you regularly export solar during the day and buy electricity later at a higher price. It is less compelling when daytime self-use is already high or export payments are generous. Judge it with your own half-hourly use, tariffs, usable capacity, losses, warranty and installed price.

Battery creates energy?
No — it shifts it
Main inputs
Surplus, demand and tariffs
Compare first
A better export tariff
Use in calculations
Usable capacity
By the UKSolars editorial team Updated 2026-09-09
Sources checked 2026-09-09
Installer checking a wall-mounted home battery and electrical equipment in a British utility room
Battery design must account for the existing inverter, consumer unit, usable capacity and network connection. · Original UKSolars editorial image

Treat a battery as a time-shifting device. It stores electricity that would otherwise be exported, or electricity bought at a cheap time, and supplies it later.

The calculation that matters

For solar charging, compare the import cost avoided with the export income given up. Apply conversion losses, then multiply by the amount the battery can realistically shift over a year. Compare that annual value with the installed price and warranty period.

Use smart-meter or monitoring data if available. Annual household use alone does not show how much spare solar exists at midday or how much electricity is needed after sunset.

A battery is more likely to help when

  • substantial solar is exported on many days;
  • electricity use rises after solar generation falls;
  • import and export prices leave a useful spread; and
  • the battery is sized to cycle regularly rather than sit partly unused.

It may be poor value where daytime self-use is already high, surplus is small, or a better export tariff closes much of the price gap.

Backup is not automatic

Many grid-connected batteries shut down during an outage unless the design includes suitable backup equipment and dedicated circuits. If resilience matters, require the quote to state what remains powered and for how long.

Compare the current battery cost guide and choose a size from measured surplus and demand, not a generic household label.

Common questions

Does a battery make solar panels generate more?
No. It stores energy for later and incurs conversion losses. Its value comes from changing when you import or export electricity, not from increasing panel generation.
Can a battery charge from the grid?
Many systems can, subject to the product settings, tariff and network arrangement. Cheap-rate charging can change the economics, but model round-trip losses and the battery warranty rather than assuming every stored unit is free.

Sources

Checked 2026-09-09. Rates, rules and eligibility can change. Confirm current terms before signing a contract or applying for funding.

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