Blog · 2026-01-15 · 7 min
Specific yield explained: what one kWp really produces where you live
kWh per kWp per year is the bridge between panel size and annual generation — and it varies sharply by climate and roof.
Definition
Specific yield is annual AC electricity produced per kilowatt-peak of DC panels, in kWh/kWp/yr.
If you have 6 kWp and a yield of 950, expected year-1 generation is about 5,700 kWh before degradation.
Typical mid-range bands
These are planning ranges for south-facing arrays around ~35° tilt — not guarantees:
- Central Europe: ~950–1,050
- UK & Ireland: ~850–950
- Southern Europe: ~1,300–1,500
- US Southwest: ~1,500–1,700
WattPayback's region selector sets a mid-point of each band. Change it if your orientation, tilt, shading or snow losses differ.
Losses people forget
Nameplate DC capacity is not what reaches the meter. Inverter efficiency, cabling, soiling, temperature and shading all sit inside a realistic specific yield. A PVGIS or similar simulation for your exact roof is better than any regional default.
Use the system size estimator once you have a yield you trust.