Frequently Asked Questions (FAQ) – SolarGuard Online Shop and Installation

Solar thermal collectors offer significantly better efficiency, with an efficiency of 80% , compared to the 14 to 22% efficiency of photovoltaic modules. Therefore, a solar thermal system requires much less roof space than a photovoltaic system.

Even after 20 years of subsidies , you can continue to sell your generated PV electricity to the public grid . Feeding all the electricity into the grid can remain a valuable source of income even after the end of the EEG subsidy.

Photovoltaics is a technology that converts light energy into electrical energy . Sunlight is most commonly used as the energy source, but solar cells can also work with artificial light sources – such as lasers.

The cost of a 10 kWp photovoltaic system with storage, including installation, ranges from €14,000 to €17,000 . Installation costs average between €2,000 and €2,500. The difference compared to smaller systems is minimal. For example, installing a 5 kWp photovoltaic system costs approximately €1,500 to €1,750.

Home energy storage systems can help reduce energy costs by storing excess electricity when prices are lower (e.g., at night) and using it during peak hours with higher prices . This allows homeowners to benefit from time-of-use tariffs and potentially reduce their monthly electricity bills.

These systems are environmentally friendly, durable, require little maintenance, and are more affordable due to subsidies. Disadvantages include high initial costs, weather-dependent yields, and limited storage capacity . Space requirements and aesthetic considerations can also play a role.

How much photovoltaic system do I need for a detached house in Germany? For a detached house with an electricity consumption of 3,000 kWh per year, you need approximately 4 to 5 kWp of photovoltaic system. For a consumption of 5,000 kWh, you need around 7 to 8 kWp, and for 10,000 kWh, approximately 12 to 14 kWp.

Whether and how quickly a photovoltaic system pays for itself cannot be said in general terms – it depends on many factors. However, one thing is clear: in most cases, the investment pays off relatively quickly. Amortization periods of 8 to 15 years are the norm .

A capacity of 10 kWh means that you can store an average of 10,000 watt-hours of energy – enough to power an average 3-person household for about 10 to 12 hours .

To use your car as a storage device, you need an electric car that can charge bidirectionally, meaning it can both charge and discharge, and a bidirectional wallbox including an inverter . Only then can you use the electric car as a mobile storage device.

Even after 20 years of subsidies , you can continue to sell your generated PV electricity to the public grid . Feeding all the electricity into the grid can remain a valuable source of income even after the end of the EEG subsidy.

A balcony PV system ("plug-in solar device") is generally only economically viable if the self-generated electricity is also consumed directly in the household – especially during the daytime.

The system produces the most electricity in sunny weather, with a peak around midday. Without battery storage, excess solar power is fed into the grid, which generates hardly any revenue due to the low feed-in tariff.

Therefore, installation without storage is particularly worthwhile for households that have a high electricity demand during the day, e.g. if:

• Someone is working from home.
• A person (e.g., in the household) is regularly at home during the day.
• Appliances such as washing machines, dishwashers or air conditioners can be operated specifically in sunlight.

If the household is mostly empty during the day (all residents are out at work), the majority of the solar power is fed into the grid and not used directly. In this case, purchasing a balcony solar system without a battery storage system is often not economical.

Summary: The greatest financial benefit comes from direct self-consumption during production time. Therefore, examine your daily consumption patterns before making a decision.

Yes, registration is legally required! It must be done in two steps:

1. Contact your grid operator: Before commissioning, use a simplified form. Visit verbraucherzentrale.de → Search for "plug-in solar device" or "balcony solar". Purchase the device and register it with your grid operator before connecting it .
2. At the Federal Network Agency (Market Master Data Register): Registration must take place within one month of commissioning.
   Failure to register may result in the network operator refusing connection. Furthermore, in the event of damage (e.g., fire), you risk problems with your insurance. marktstammdatenregister.de

Yes, both are possible.

• Facade: Secure and stable mounting with a suitable support system is essential. The yield is somewhat lower than with optimal south-facing orientation, but often still very good (especially for east- or west-facing facades). The building's structural integrity and the penetration of the building envelope must be assessed.
• Terrace: Freestanding systems (e.g., stands with triangular bases) that are not permanently attached to the building are suitable here. This is often the simplest solution and avoids complex structural considerations. Ensure stability against wind.

Yes, the modules also produce electricity in diffuse light, but significantly less (approximately 10-25% of maximum output). In winter, shorter days, lower sun angle, and potential snow cover result in lower yields. However, the system provides a basic contribution to the electricity supply year-round.

For balconies , monocrystalline modules are almost always the better choice. They have a higher efficiency (more power in the same area), slightly better performance in low light, and are more space-saving. Polycrystalline modules are often cheaper to buy, but require more surface area for the same power output.

No, absolutely not. Standard plug-in solar panels are capable of "off-grid" operation. In the event of a power outage, the inverter shuts down for safety reasons to prevent electricity from being fed back into the deactivated grid and potentially endangering workers on the power lines. Special, expensive off-grid systems with batteries are required for emergency power supply.

Yes, they exist! With a special system, you can also use your solar power during a grid outage. The solution is called: "Emergency power or off-grid capable inverter with battery storage".

Here's how it works:

1. Special inverters: A conventional balcony inverter switches off during a power outage. The desired solution requires a hybrid inverter that enables "island operation." This detects the power outage and automatically disconnects from the public grid to establish a safe, independent power circuit (the "island").
2. Battery storage is essential: Since the sun doesn't always shine, this system absolutely requires a battery storage system (e.g., a lithium-ion battery). This stores the solar power generated during the day and makes it available when needed, even at night or in the event of a power outage.
3. Separate circuit: In the event of an emergency power supply, the system usually only supplies selected sockets or a special sub-distribution panel in the house (e.g., for refrigerator, lights, router). It rarely provides full power to the entire house.

Maintenance is minimal. Heavy soiling (e.g., bird droppings, dust) can reduce energy yield. Clean the modules on overcast days or in the early morning with a soft sponge, water, and, if necessary, a little glass cleaner. Do not use hard water (limescale deposits) or a pressure washer, as these can damage the modules.