Solar yield
kWh per kWp: solar yield by city and roof direction
Yield in kWh per kWp is the quickest way to compare roofs and places. These figures come from PVGIS satellite records for 16 cities and every main roof direction.
By SunCast team Last updated: October 19, 2026
Short answer
A south-facing solar system produces about 987 kWh per kWp a year in London, 1,014 in Berlin, 1,549 in Madrid and 1,742 in Phoenix. East- or west-facing roofs produce about 21% less than south, and north-facing roofs at 35° about 49% less. Multiply the figure by your system size in kWp to estimate its yearly output.
Terms used on this page
| Term | Meaning |
|---|---|
| kWp | Kilowatt peak: the rated power of a solar system under standard test conditions. Ten 450 W panels make a 4.5 kWp system. |
| kWh per kWp | Energy a system produces in a year for each kWp installed, also called specific yield. It lets you compare roofs and places regardless of system size. |
| System loss | Losses from cables, the inverter and dirt. The figures here assume 14%, a common planning value. |
| PVGIS | The European Commission's photovoltaic tool. These figures use its PVGIS-SARAH3 satellite records from 2005 to 2023. |
Yearly kWh per kWp by city and roof direction
Each figure is the average yearly output of 1 kWp of panels on a roof pitched at 35°, or lying flat in the last column.
| City | South | SE or SW | East or west | North | Flat |
|---|---|---|---|---|---|
| London, UK | 987 | 929 | 782 | 532 | 824 |
| Manchester, UK | 861 | 814 | 693 | 487 | 728 |
| Edinburgh, UK | 878 | 823 | 686 | 466 | 719 |
| Dublin, Ireland | 954 | 895 | 747 | 509 | 784 |
| Amsterdam, Netherlands | 992 | 935 | 791 | 528 | 833 |
| Hamburg, Germany | 946 | 892 | 753 | 500 | 794 |
| Berlin, Germany | 1,014 | 954 | 799 | 526 | 846 |
| Munich, Germany | 1,096 | 1,030 | 863 | 573 | 920 |
| Paris, France | 1,091 | 1,026 | 863 | 580 | 924 |
| Budapest, Hungary | 1,201 | 1,124 | 937 | 608 | 1,003 |
| Milan, Italy | 1,308 | 1,222 | 1,010 | 640 | 1,086 |
| Madrid, Spain | 1,549 | 1,456 | 1,216 | 774 | 1,310 |
| Seville, Spain | 1,597 | 1,505 | 1,272 | 827 | 1,377 |
| New York, US | 1,344 | 1,253 | 1,030 | 639 | 1,118 |
| Denver, US | 1,735 | 1,617 | 1,320 | 763 | 1,415 |
| Phoenix, US | 1,742 | 1,645 | 1,392 | 865 | 1,516 |
Roof-mounted panels, 14% system loss, shading by distant terrain included, no nearby trees or buildings. South-east and south-west, and east and west, are averaged.
How roof pitch changes the yield
Yearly kWh per kWp at different pitches, facing south and facing east or west.
| Pitch | London south | London east or west | Madrid south | Madrid east or west |
|---|---|---|---|---|
| Flat | 824 | 824 | 1,310 | 1,310 |
| 15° | 924 | 814 | 1,465 | 1,289 |
| 30° | 980 | 793 | 1,541 | 1,239 |
| 45° | 987 | 753 | 1,538 | 1,162 |
| 60° | 947 | 690 | 1,454 | 1,054 |
East and west roofs lose less on shallow pitches, which is why low east-west mounting is common on flat roofs.
How to use kWh per kWp
Multiply the yield for your area and roof direction by the system size. A 4 kWp south-facing system in London produces about 3,900 kWh a year; the same system facing east or west produces about 3,100 kWh.
To find the system size, divide the usable roof area by about 2 m² (21.5 sq ft) per panel and multiply the panel count by its rating. Fifteen 450 W panels need about 30 m² (320 sq ft) and make 6.75 kWp.
Direction matters more than pitch
Across these cities, south-east and south-west roofs lose about 6% against south, east and west roofs about 21%, and north roofs at 35° about 49%. Pitch changes the result less: in London a south roof at 15° yields about 6% less than one at 30°.
An east-west roof has two usable faces, so the total can match or exceed a single south face of the same house, with output spread across the morning and evening.
Worked examples
Terraced house in Manchester
A 3.6 kWp south-west system at 35° produces about 2,900 kWh a year.
East-west roof in Berlin
Two 4.5 kWp faces, one east and one west, produce about 7,200 kWh a year together.
Flat roof in Phoenix
A 6 kWp system lying flat produces about 9,100 kWh a year, against 10,500 kWh when tilted south at 35°.
Limits
These are long-term averages for an unshaded roof. Trees, chimneys and nearby buildings, panel ageing, inverter clipping and a particularly cloudy year can all lower the real figure. Use the calculator for your exact address, and a professional survey before buying.
Check it in SunCast
Want the figure for your own roof? The SunCast solar roof calculator works out monthly and yearly output for each roof section at your address, and the SunCast app shows sun paths and shadows on the real roof.
Frequently asked questions
What is a good kWh per kWp?
It depends on the location. For a south-facing roof, around 861 to 987 kWh per kWp is typical in the UK, 946 to 1,096 in Germany and 1,549 or more in southern Spain.
How many kWh does a 4 kW solar system produce in a year?
About 3,900 kWh in London, 4,100 kWh in Berlin and 6,200 kWh in Madrid on a south-facing roof.
Are east-west solar panels worth it?
Each panel produces about 21% less than facing south, but using both faces of the roof often gives a larger system and a flatter daily output.
Do north-facing solar panels work?
They produce about 49% less than south at 35°. On a shallow roof the gap is smaller, so they can still be worth including.
