Solar only, battery only, or both?

Last reviewed 7 October 2026. Written for Herne Bay, Kent. Figures are estimates, not quotes.

Short answer. For most houses, solar first gives the best return. Add a battery at the same time if nobody is in by day or you have an electric car. A battery alone makes sense if you already have panels, or can fill it cheaply overnight. Prices: solar £5,500 to £7,500, both £8,500 to £12,500, battery only £2,750 to £4,750.

White wall-mounted home battery and inverter beside a small consumer unit on the pebbledash garage wall of a 1960s bungalow, with a bicycle and a view over the coast

In this guide

Solar only: the steadiest return
Solar and battery together
Battery only: two cases that stack up
Neither fits? Try plug-in solar

Solar only: the steadiest return

Panels earn their keep while the sun is up and you are using power. A 4 kWp system costs about £5,500 to £7,500 and, on our model, pays back in roughly 9 to 12 years. If someone is at home in the day, little else on this site beats it.

Solar and battery together

A battery keeps the afternoon surplus for the evening. Bought with new panels it shares the scaffold, the electrician and the paperwork, so £8,500 to £12,500 for both is less than the two prices added together. The payback is longer, about 11 to 16 years, so you are buying evening power, flexibility and backup more than speed.

Battery only: two cases that stack up

First, you already have solar and send much of it back to the grid. Second, you have a smart meter and can charge overnight cheaply. Our model gives £2,750 to £4,750 for 5 kWh, paying back in 25 to 43 years on panels you already own, or 12 to 21 years with a cheap overnight rate as well. The Energy Saving Trust puts a battery's typical life at 10 to 12 years, so hold the payback up against that.

Neither fits? Try plug-in solar

A plug-in kit costs from about £450 and saves about £70 to £100 a year, says the Energy Saving Trust. It suits a flat or a small garden, within the planning limits on our plug-in page.

Questions people ask

Can I add a battery later?

Usually, but an older inverter may not suit one. Fitting both together is normally cheaper than coming back for a battery.

Which pays back fastest?

Solar only. A battery on its own is the slowest unless you fill it on a cheap overnight rate.

Should I wait?

If you want solar, the 0% VAT end date of 31 March 2027 is the only hard deadline. Quotes, surveys and network notice take weeks.

Want numbers for your own house? Try the estimator or ask for a free quote.

Solar only, battery only, or both?

Solar only: the steadiest return

Solar and battery together

Battery only: two cases that stack up

Neither fits? Try plug-in solar

Questions people ask

Sources

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