June 16, 2025, 10:40 am | Read time: 2 minutes
Do Solar Panels Only Pay Off on a South-Facing Roof? Is That Really True? There are several common misconceptions about these systems. myHOMEBOOK clarifies.
The demand for renewable energy has steadily increased in recent years. Solar energy, which can be harnessed through photovoltaic systems, is particularly popular. However, over the years, several misconceptions about this type of energy supply have crept into the public consciousness.
1. Misconception: “Thanks to the system on the roof and storage, I am independent”
This assumption is not entirely correct, according to the Consumer Center NRW. A photovoltaic system can only cover a certain portion of a household’s annual electricity supply—even with an attached battery storage.
“This is referred to as the degree of self-sufficiency, which can range from 25 to 90 percent, depending on whether storage is available and the level of electricity consumption,” states the Consumer Center. The remaining necessary electricity must still be purchased from the grid. Especially during the cold season, systems in Germany produce too little electricity. Thus, an entire household cannot be supplied, even with battery storage.
2. Misconception: “A south-facing roof is always better than an east-west roof”
While a photovoltaic system on a south-facing roof generates about 20 percent more electricity than on an east-west roof, private households are primarily concerned with their own use of the electricity.
The Consumer Center points out significant advantages of the east-west roof: With this setup, the electricity generation is spread throughout the day. Early in the morning and later in the day, the system receives more sunlight. This allows for more self-consumption of electricity.
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3. Misconception: “A system is only worthwhile with a battery storage”
A photovoltaic system is financially worthwhile even without storage. Whether an additional electricity storage is profitable depends on the individual case. On one hand, battery storage often involves high acquisition costs. On the other hand, storing and later self-consuming electricity can be beneficial. For new photovoltaic systems, the compensation for a kilowatt-hour of fed-in electricity is less than 10 cents, while grid electricity often costs around 40 cents per kilowatt-hour.