The cost picture in 2025
Solar panel costs have fallen by over 90% since 2010. A typical residential system — 4kW peak — now costs between £5,000 and £8,000 installed. The payback calculation has improved further because electricity prices are significantly higher than in 2019, meaning each unit of electricity generated and used in the home is more valuable.
Typical payback periods
For a south-facing roof with good solar irradiance and no significant shading, a well-sized system can achieve payback in 7-12 years, depending on your electricity tariff and how much electricity you use during daylight hours.
The Smart Export Guarantee
The Smart Export Guarantee requires energy suppliers with over 150,000 customers to offer a tariff for electricity exported to the grid by small generators including solar panels. Rates vary between suppliers and are typically 3-15p per unit — making maximising self-consumption the priority for economics.
Battery storage
Adding a battery to a solar system costs an additional £3,000-£7,000 and allows you to store electricity generated during the day for use in the evening. Whether it makes financial sense depends on your tariff structure and self-consumption without the battery.