UK Residential Solar
System Size
Calculator
Calculate the right solar PV system size for a UK home. Based on real UK solar irradiance data — covering England, Wales, Scotland, and Northern Ireland.
Your Energy Usage
Enter your annual electricity consumption, or let us estimate it from your household size.
Annual electricity usage
?
Check your energy bills or smart meter. UK average: ~3,500 kWh/yr
kWh
Roof & Location
These factors affect how much sunlight your panels will capture throughout the year.
Region
?
Roof orientation
?
Roof pitch
?
Shading
?
Desired solar coverage
?
How much of your annual electricity usage should solar cover?
Your Results
System size
—
kilowatt-peak
Panels needed
—
× 400W panels
Est. generation
—
kWh per year
Coverage
—
of annual usage
Estimates are based on standard UK solar irradiance data and a typical system performance ratio of 0.85. Actual system size and output will vary by site. Always consult a qualified MCS-accredited installer for a full assessment.