Question 1

What roof orientation is best for solar panels?

Accepted Answer

The optimal direction for solar panels is due south (180° azimuth). Deviations of up to 45° east or west reduce yield by only about 5–10%. Even pure east- or west-facing roofs still achieve around 80% of the maximum possible output.

Question 2

What tilt angle produces the highest solar yield?

Accepted Answer

In Central Europe, the optimal tilt angle is 30–35°. Shallower angles (15–20°) generate more in summer, steeper ones (40–50°) more in winter. The annual difference between 20° and 40° is usually less than 5%.

Question 3

How much electricity does a solar system produce per kWp per year?

Accepted Answer

In Germany, an optimally oriented solar system generates about 900–1,100 kWh per kWp per year. In southern Germany and Austria up to 1,200 kWh/kWp is possible, in Northern Europe rather 800–950 kWh/kWp. The exact value depends on location, roof orientation, tilt angle, and shading.

Question 4

What does self-sufficiency (autarky) mean for a PV system?

Accepted Answer

The self-sufficiency rate indicates what percentage of your own electricity consumption is covered directly by the solar system. Without storage it is typically 25–35%, with a battery 50–70%. The higher the self-consumption share, the more economical the system operates.

Question 5

Is a battery storage system worth it for my solar installation?

Accepted Answer

A battery storage system significantly increases self-consumption and self-sufficiency. For a typical 4-person household with a 5–10 kWp PV system and 5–10 kWh storage, the self-sufficiency rate rises from about 30% to 60–70%. Whether storage pays off financially depends on electricity prices, storage costs, and the feed-in tariff.