Solar photovoltaic (PV) panels have become one of the most popular home energy investments in the UK, driven by rising electricity prices and falling panel costs. A well-designed system can cover 25-50% of a typical household's electricity demand and earn income through the Smart Export Guarantee. Here is what you need to know before you buy.
Need a tradesperson for this?
Bizzy Day lets you search available UK tradespeople by trade, postcode, and date — free, no account needed.
Find a tradesperson — freePlanning permission for solar panels
In most cases, solar panels on a domestic roof fall under permitted development and do not need planning permission, provided they: do not protrude more than 200mm beyond the roof plane; do not exceed the highest point of the roof; are removed when no longer needed; and are sited to minimise their effect on the appearance of the building when in a Conservation Area. Listed buildings require Listed Building Consent.
System sizing
A typical UK home uses 3,500-4,000 kWh of electricity per year. A 4-5 kWp solar system will generate 3,500-4,500 kWh per year in the UK, depending on location, orientation, and shading. South-facing, unshaded roofs generate the most. East/west split installations also work well. A good installer will model your roof's solar resource and design the system to match your consumption profile.
A 4kWp solar installation in the UK generates enough electricity to offset around 40-50% of an average household's annual electricity use — more if the household shifts usage to daytime.
— Energy Saving Trust
Costs and payback
A 4kWp system currently costs £6,000-£10,000 installed. Battery storage adds £3,000-£8,000. The Smart Export Guarantee (SEG) pays you for electricity you export to the grid — rates vary by supplier (typically 4-15p/kWh). Payback periods are typically 7-12 years without a battery, and slightly longer with one. However, with rising electricity prices, payback periods have been shortening.
Battery storage
A home battery stores solar-generated electricity for use in the evening when panels are not generating. Popular options include the Tesla Powerwall, Givenergy, SolarEdge, and Sonnen. Battery storage is most financially justified in homes that use significant electricity in the evening and morning, and those with time-of-use tariffs (charging cheaply overnight, using battery power at peak times).
Use an MCS-certified installer
To access the Smart Export Guarantee and most financing products, you must use an MCS-certified solar installer. This also ensures the system is designed and installed correctly. Get at least three quotes — system specifications, panel brands, and inverter quality vary significantly at similar prices.