Solar panel savings calculator

Your location

Number of panels

System size (kWp)

Most domestic systems are 4–6 kWp (10–15 panels).

Panel output

Import rate (p/kWh)

Export rate (p/kWh)

System installation cost (optional)

Including a cost enables payback period calculation.

Estimated annual saving

—

Annual generation

—

Self-consumed

—

Exported to grid

—

CO₂ offset

—

Import saving

—

Export income

—

Assumes 30% self-consumption (65% with battery), south-facing optimal orientation unless adjusted above, and rates shown. Shading is not modelled — results may be optimistic if your roof is partially shaded.

This calculator estimates how much electricity a solar panel system would generate at your location, based on long-term irradiance data from the EU's PVGIS database. Annual generation depends on your system size, roof orientation, and local sunlight levels — a well-positioned system in southern England typically generates around 850–1,050 kWh per kilowatt-peak installed.

Shading from trees, chimneys, or neighbouring buildings can significantly reduce output and isn't modelled here — if shading is a factor, treat the result as an upper estimate. Self-consumption figures (how much of your generated electricity you use directly) depend heavily on your household's daytime energy use and will vary. Electricity rates shown are regional averages; your actual saving will depend on your supplier's import and export tariff.