Updated · 3 min read
In short
- In the northern hemisphere, south-facing panels give the highest annual yield.
- South-east and south-west usually lose only a few percent; east-west yields less per year but spreads output across the day.
- The optimum tilt for annual yield in central Europe and the UK is roughly 30–40°; your roof pitch is usually close enough.
Orientation
- South: highest annual yield, peak at midday.
- South-east / south-west: small losses; south-west shifts output towards the afternoon, when household use rises.
- East-west (half on each slope): lower annual yield, but a broader curve with less midday export.
- North: avoid on steep roofs; sometimes acceptable on very shallow pitches.
Tilt
The yield curve is flat around the optimum, so a 25° or 45° roof loses little. On flat roofs the angle is a trade-off: 10–15° allows closer rows (more kWp on the same area), 30° gives more per panel but needs wide row spacing.
- Steep tilt (45–60°): favours winter, snow slides off more easily.
- Shallow tilt (10–20°): favours summer, panels get dirty faster.
Shading matters more
A chimney, aerial or tree shading a few panels at key hours can cost more than an unfavourable orientation. Check shadows in December, when the sun is low. Optimisers or microinverters limit the loss to the shaded panels instead of dragging down the whole string.
Check your own roof
The European Commission's free PVGIS tool calculates yield for your exact coordinates, azimuth and tilt. Enter your roof, compare with the optimum and see the difference in kWh per year.
Frequently asked questions
Is it worth putting panels on a north-facing roof?
On shallow pitches the loss is moderate; on steep pitches yield drops significantly. Run a simulation for your exact orientation and tilt, for example in PVGIS, before deciding.
Is east-west worse than south?
It produces less per year, but spreads production over morning and evening, which can raise self-consumption. With enough roof area, more panels east-west can be a sensible choice.