South, east, or west. Everyone has an opinion about it. But which orientation actually delivers the highest yield in practice? At Solar Assistance, we decided not to rely on theory alone. On the roof of our headquarters, we installed three identical solar panels, each with a different orientation. No simulations, just real-world data collected over multiple years.
For this test, we used three identical 395 Wp panels, each equipped with a microinverter and installed under the exact same conditions. The only difference? Their orientation:
Since March 2023, we have been continuously monitoring their performance.
South remains the benchmark for maximum yield
The results over multiple years are clear. South-facing panels consistently achieve the highest yield. On average, production is around 15 to 20 percent higher than east-facing panels and 20 to 25 percent higher than west-facing panels. But… that is not the full story.
Spread of production versus peak production
While south-facing panels mainly peak around midday, east- and west-facing panels provide a broader spread of energy production throughout the day. East-facing panels generate most of their electricity in the morning, while west-facing panels peak in the afternoon and early evening. Combining both orientations spreads energy production more evenly across the day instead of creating one large peak at noon.
This difference is more important than it may seem. The better your production matches your consumption patterns, the more solar energy you can use yourself and the less electricity you need to feed back into the grid.
What does this mean for your installation?
The ideal orientation depends on your situation. Do you want the maximum yield per panel? Then south remains the best choice. Do you want to increase self-consumption and reduce dependence on grid injection? Then an east-west setup is often the more interesting option. If you have enough roof space, an east-west configuration can even generate a higher total yield per square meter.
Sunshine hours make the difference
Besides orientation, the number of sunshine hours also plays a major role. In 2024, we recorded 1,365 sunshine hours. In 2025, that number increased to 1,838. More sunshine naturally leads to higher yields, regardless of panel orientation. However, it is striking that the increase in production does not fully keep pace with the increase in sunshine hours.
The hidden efficiency loss
An important nuance in this test: the panels have never been cleaned since installation. We do not see a sudden drop in performance, but we do notice a slight slowdown in yield growth. This points to dirt accumulation as a possible cause of performance loss.
“Installing solar panels is one thing. Ensuring they continue to perform optimally year after year is just as important,” says Jürgen Donné, CEO of Solar Assistance.
That is why we are currently conducting additional tests on the long-term impact of cleaning solar panels.
Conclusion: orientation matters, but it is not everything
South remains the best choice for maximum yield per panel. East-west is often the smartest choice for those focusing on self-consumption and overall return. But in practice, the biggest difference is not only determined by panel orientation. The real return depends on what happens afterwards: monitoring, maintenance, and follow-up. That is often where the greatest gains can be achieved.
