---
title: Solar PV and battery storage
stability: figures likely to go stale — installation costs, export tariff rates and the details of subscription-style offers change often; the "questions to ask" section is durable, but cost/payback numbers should be re-checked before reuse
---

# Domestic solar PV and battery storage

## How it works

Solar photovoltaic (PV) panels convert sunlight into direct current (DC) electricity, which a solar inverter converts to alternating current (AC) to run household appliances or export to the grid. Panels still generate some electricity on cloudy days, and UK systems keep producing for 25 years or more, with the inverter typically needing replacement every 10-12 years. A battery, if fitted, stores excess daytime generation so it can be drawn on in the evening instead of buying electricity from the grid.

## Payback considerations

A typical domestic system (around 4.5 kWp) costs roughly £7,600 to install. Energy Saving Trust's guidance is that payback time varies by location and how much generated electricity the household uses rather than exports — commonly around 9-12 years. Adding a battery raises the upfront cost and shifts more saving toward self-consumption, but batteries typically need replacing sooner than panels, affecting the whole-system payback. Exported electricity can usually be paid for through a supplier's Smart Export Guarantee (SEG) tariff, which requires MCS certification and a smart meter capable of half-hourly export readings.

## "No-upfront-cost" battery and solar subscription offers

Some companies offer solar and/or battery installation with no upfront payment, recovering the cost through a monthly subscription, a share of bill savings, or payments for letting the supplier use the battery to help balance the grid (sometimes marketed as joining a "virtual power plant" or VPP). This is a legitimate category of offer, but because the household doesn't own the equipment outright, it's worth checking the details before signing. Sensible questions: how long is the contract and what are the exit terms; what happens to the battery and your home's power during a grid power cut, since not all systems provide automatic backup; where the equipment is manufactured and sourced; who owns and maintains it, and what happens to any warranty; and whether the installer is MCS-certified and signed up to a recognised consumer protection code, such as the Renewable Energy Consumer Code (RECC). The UK saw comparable "rent-a-roof" solar schemes in the 2010s, where long roof leases and unclear buyout terms later complicated some homeowners' ability to sell or remortgage — a reminder that contract fine print matters as much as the headline saving.

## Sources

- [Solar panels: costs, savings and benefits explained — Energy Saving Trust](https://energysavingtrust.org.uk/advice/solar-panels/)
- [Battery storage — Energy Saving Trust](https://energysavingtrust.org.uk/advice/battery-storage/)
- [Smart Export Guarantee (SEG) — GOV.UK](https://www.gov.uk/government/publications/smart-export-guarantee-seg-earn-money-for-exporting-the-renewable-electricity-you-have-generated)
- [MCS — UK's quality mark for small-scale renewables](https://mcscertified.com/)
- [Free solar panels and solar buyback explained — Which?](https://www.which.co.uk/reviews/solar-panels/article/solar-panels/free-solar-panels-and-solar-buyback-at94w3z47cFS)

Facts current as of: 2026-09-20