☀️ In brief: A 10 kWp system with 10 kWh storage costs around €18,000 – 22,000 net in 2026. With a self-consumption rate of 70%+, the investment pays for itself in about 12 – 14 years — often faster with rising electricity prices.
Why PV Is More Relevant Than Ever in 2026
Three developments make photovoltaics particularly attractive in 2026: First, electricity prices continue to rise. Household electricity currently costs around 35 – 38 ct/kWh — with an upward trend. Second, module prices have dropped massively in recent years: While the price per watt peak was around €1.50 in 2021, you now pay well under €1.00/Wp. Third, the federal government's climate goals make expanding renewable energy mandatory — and homeowners benefit directly.
At the same time, storage technology has improved significantly. Lithium iron phosphate batteries (LFP) have become more durable, safer, and cheaper. Combined with a PV system, they allow you to use self-generated electricity in the evening and at night — significantly increasing your self-consumption rate.
Bottom line: The combination of high electricity prices, low system costs, and mature storage technology makes 2026 an excellent time to invest in PV.
What Does a PV System with Storage Cost?
Costs depend on system size, storage capacity, roof conditions, and regional installation prices. For a typical single-family home with a 10 kWp system and 10 kWh battery storage, the cost breakdown in 2026 looks roughly like this:
💡 Good to know: Since January 2023, a zero VAT rate applies to PV systems up to 30 kWp. This means: You pay 0% VAT on purchase and installation — the net prices listed above are your actual costs.
Self-Consumption vs. Feed-In
Whether your PV system pays off depends crucially on how much of your self-generated electricity you actually use yourself. The feed-in tariff in 2026 is only around 6 ct/kWh — but your household electricity costs you 35 – 38 ct/kWh. Every kilowatt-hour you consume yourself instead of feeding in saves you about 29 – 32 ct.
Without Storage: ~25 – 35% Self-Consumption
Without a battery, you only use the electricity generated at the exact moment you consume it. During the day when the sun is shining, many households are away from home. In the evening and at night, when consumption increases, the system produces no electricity.
With Storage: 60 – 80% Self-Consumption
A battery storage system buffers the excess generated during the day and makes it available in the evening and at night. This typically increases your self-consumption to 60 – 80%. The exact rate depends on your household's consumption profile and storage size.
☀️ Rule of thumb: The storage should have approximately 1 kWh capacity per kWp of system output. At 10 kWp, 10 kWh is a good benchmark. Oversized storage increases costs without proportionally boosting self-consumption.
Calculation Example: Single-Family Home in Siegen
Let's take a concrete example: A single-family home in Siegen with an annual electricity consumption of 4,500 kWh. A 10 kWp system with 10 kWh storage is installed on the south-facing roof.
(approx. 900 kWh/kWp in the Siegen region)
(70% of 4,500 kWh annual consumption)
(3,150 kWh x €0.36/kWh)
(5,850 kWh x €0.06/kWh)
(Savings + feed-in revenue)
With investment costs of around €20,000 and an annual benefit of about €1,485, the payback period is approximately 13 – 14 years. Since modules deliver performance for 25 – 30 years, you'll generate pure profit for at least 12 – 17 more years after that. If electricity prices continue to rise, the payback period shortens accordingly.
📊 Return: Over the system's lifetime, this corresponds to a return of about 5 – 7% per year — significantly more than many traditional investments.
Subsidies and Tax Benefits
Even though direct investment grants for PV systems have largely expired in recent years, there are still attractive funding options and tax benefits:
KfW Loan 270 — Renewable Energies
KfW offers low-interest loans for PV systems and battery storage. The terms are often below market rates. The application goes through your bank — important: apply before signing the purchase contract!
Zero VAT Rate Since 2023
Since January 2023, no VAT is charged on the purchase and installation of PV systems up to 30 kWp and associated battery storage. This effectively reduces investment costs by around 16% compared to the old regulation.
Income Tax Exemption
Since 2023, income from PV systems up to 30 kWp on single-family homes (or 15 kWp per residential unit in multi-family homes) is exempt from income tax. This means: No profit calculation, no Annex V needed — a significant simplification.
Regional Subsidies NRW
Some municipalities and local utilities in NRW offer additional grants for PV systems and storage. Programs change frequently — it's worth asking the city of Siegen and local utilities about current offerings.
PV and Heat Pump: The Dream Team
If you're already thinking about a new heating system, you should plan PV and heat pump together. The synergy is enormous: A heat pump consumes about 3,000 – 5,000 kWh of electricity per year. If a large portion comes from your own PV system, heating costs drop dramatically — and the self-consumption rate rises to 80% and above.
Particularly clever: In summer, the PV system generates the most electricity, and the heat pump can use it for hot water. During transitional seasons (spring/autumn), PV covers a large portion of the heating demand. Only in deep winter does more grid electricity need to be purchased — but even then, costs are far below those of a gas or oil heating system.
🔥 Tip: For the PV + heat pump combination, we recommend a slightly larger system (12 – 15 kWp) and a larger storage (12 – 15 kWh). The additional cost pays for itself quickly through higher savings.
What to Consider When Planning
Before commissioning a PV system, some important points should be clarified:
Roof Orientation and Pitch
Ideal is a south-facing orientation with 30 – 35° pitch. But east-west roofs are also economical: The yield is only about 15 – 20% below south, but electricity generation is distributed more evenly throughout the day — advantageous for self-consumption.
Check for Shading
Trees, chimneys, neighboring buildings, or antennas can shade individual modules. Even minor shading can significantly reduce yield. A professional shading analysis before installation is therefore essential.
Roof Condition and Structure
The roof covering should last at least 20 more years — roof renovation after PV installation is expensive. The structure must also be able to bear the additional load (approx. 12 – 15 kg/m²).
Grid Connection and Meter
Your grid operator must approve the system and install a bidirectional meter. This is usually straightforward but can take a few weeks. Plan for this lead time.
Fire Safety and Insurance
PV systems must meet fire safety requirements (e.g., distance to neighboring buildings). Also inform your building insurance — most policies cover PV systems for a small additional premium.
Note: All prices, yields, and subsidy conditions mentioned reflect the status as of June 2026 and are subject to change. The calculations serve as a guide — actual profitability depends on your individual circumstances. We recommend a personal consultation for a binding calculation.
Is PV Worth It for Your Home?
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