Per kW, your region950 kWh
4.5 kW system, per year4,275 kWh
Worth if used at home£1,125
Your region
Worked out for UK average at today's electricity price of 26.32p per kWh. South-facing roof, no shade.
By region
Typical yearly output for each kW of panels on a south-facing roof:
| Region | Per kW per year | 4.5 kW system per year |
|---|---|---|
| South West and South of England | about 1,050 kWh | about 4,700 kWh |
| London and South East | 950 to 1,050 kWh | about 4,500 kWh |
| Midlands and Wales | 900 to 1,000 kWh | about 4,300 kWh |
| North of England | 850 to 950 kWh | about 4,050 kWh |
| Northern Ireland | 850 to 950 kWh | about 4,050 kWh |
| Central Scotland | 800 to 900 kWh | about 3,800 kWh |
East or west-facing roofs make roughly 15 to 20% less than south-facing ones, but still work well.
Summer vs winter
Around 69% of a typical system's yearly output comes between April and September, according to Utilita. A sunny June day can produce five times as much as a grey December one. See do solar panels work in winter?
What about cloudy days?
Panels still generate in daylight when it's cloudy, just less. The UK figures above already include typical British weather.
Sources: Reonic regional yield table, Utilita, Octopus Energy tariff data.