The average cost of a solar panel system in the UK in 2026 ranges from £4,000 to £8,000 for a typical 3kW to 4kW system, depending on the quality of the panels, the complexity of the installation, and whether you include a solar battery. A larger 6kW system typically costs between £8,000 and £12,000. Prices have fallen significantly over the last decade, and you may be able to export electricity for free under the Smart Export Guarantee.

A typical 4kW solar panel system in the UK can generate around 3,400 kWh of electricity per year. If you use about 70% of this energy directly in your home (avoiding buying it from the grid at ~25p/kWh) and export the remaining 30% under the Smart Export Guarantee (at ~5p/kWh), you could save around £750 to £900 per year on your electricity bills. The exact savings depend on your electricity tariff, how much energy you use during the day, and your household’s consumption patterns.

The Smart Export Guarantee (SEG) is a UK government-backed scheme that requires large energy suppliers to pay you for the renewable electricity your solar panels generate and export back to the national grid. The rates vary between suppliers, typically ranging from 1p to 15p per kWh. By getting a smart meter, you can ensure you are paid for every unit of green energy you export.

The payback period for solar panels in the UK is typically between 9 and 14 years. With an average system cost of £6,000 and annual savings of £500 to £800, the system will pay for itself in under a decade. Since solar panels have a lifespan of 25 to 30 years, you can expect 15 to 20 years of virtually free electricity after the payback period is reached.

A typical 4kW solar panel system saves around 750 kg to 800 kg of CO2 per year compared to using electricity from the UK national grid. Over their 25-year lifespan, this equates to over 18 tonnes of carbon emissions avoided. As the UK grid continues to decarbonise, the relative carbon savings of solar panels remain highly significant in helping to reach net-zero targets.

Yes, solar panels still work in the UK winter, although they generate less electricity than in the summer. Solar panels use daylight, not heat, to generate electricity. While winter days are shorter and the sun is lower in the sky, a well-installed system will still generate a meaningful amount of power between October and March, often covering your basic daytime electricity needs.

A solar battery is not strictly necessary, but it can significantly increase your self-consumption. Without a battery, you typically use about 30% to 50% of the solar energy you generate directly, exporting the rest. A battery allows you to store excess energy generated during the day to use at night, potentially increasing your self-consumption to 70% or more. However, batteries add £3,000 to £5,000 to the upfront cost, so you must calculate if the extra savings justify the investment.

As a general rule, you need about 6 to 7 square metres of unshaded roof space per 1 kWp of solar capacity. A typical 4kW system requires around 25 to 28 square metres of roof space. The panels should ideally face south, south-east, or south-west at a pitch of 30 to 40 degrees for maximum efficiency, though east and west-facing roofs will still generate good returns.