Planning Your PV System: The Complete Checklist
Thinking about installing a photovoltaic system? Good planning from the start makes all the difference. It determines how much electricity your system will generate, how economically it operates, and how reliably it runs over time. This checklist walks you through the key steps on the way to your own PV system.
Step 1: Check Whether Your Roof Is Suitable
The first question is whether your roof is suitable for a PV system at all. The key factors are usable roof area, orientation, and pitch angle. South-facing roofs with a pitch of around 30 to 35 degrees are ideal, but east- and west-facing roofs can also deliver good yields — they spread electricity generation more evenly throughout the day.
It's also important to consider potential shading from trees, neighbouring buildings, or chimneys, as these can significantly reduce energy output. Our 3D Roof Planner lets you place modules directly on your roof and see the impact of obstacles.
Beyond location and shape, the condition of your roof matters too. Before installation, check whether the roof covering will last many more years or whether renovation makes sense first. Structural integrity must also be confirmed: the roof needs to safely support the additional weight of the system. This is especially important for flat roofs, which often require additional mounting frames.
Step 2: Determine the Right System Size
The ideal size of your PV system depends primarily on your household's electricity consumption. Equally important is how much of the self-generated electricity you want to use yourself. This self-consumption ratio also influences whether a battery storage system makes sense and how large it should be. More on this in our guide on calculating battery storage size.
Don't just plan for today's consumption — consider future changes too. Additional electricity consumers like a heat pump or an EV charger can significantly increase demand. You can use our Heat Pump Calculator to estimate the actual electricity demand of a heat pump. Forward-thinking planning avoids later retrofits or an undersized system.
Step 3: Choose the Right Components
For your PV system to work reliably and efficiently, the individual components need to be well matched. The key elements are the mounting system, solar modules, and inverter.
Mounting system: It ensures the modules are securely attached to the roof and can withstand wind and weather. Look for certified mounting systems with structural verification. Without this, insurance coverage could be affected in case of damage.
Solar modules: Key factors are efficiency, output, and lifespan. The best modules for your situation depend on your roof, budget, and yield targets.
Inverter: It converts the generated DC power into usable AC power for your household. It should be appropriately sized for the system and installed in a cool, well-ventilated location.
Step 4: Calculate Costs and Financing Realistically
Cost planning should go beyond modules and inverters. Total costs include the mounting system, battery storage, installation, scaffolding, and potentially a new meter cabinet. Scaffolding costs and electrical adaptations are often underestimated in initial planning.
Beyond acquisition costs, it's worth exploring funding programmes and financing options. While federal subsidies for PV systems are currently unavailable, state or municipal programmes may still be available. The KfW development bank also offers favourable financing for certain projects.
There are also tax advantages, such as VAT exemption for many PV systems. Those who feed electricity into the grid also receive a feed-in tariff. Our profitability calculator with a 25-year projection shows whether the investment makes sense for your situation.
Step 5: Find a Reputable Installer
Demand for PV systems is high — and unfortunately so is the number of questionable offers. It pays to vet providers carefully. Be cautious if large advance payments are requested or if it's unclear which modules and components will actually be installed.
A reputable installer advises transparently, documents the planned products clearly, and typically invoices only after the work is completed. It's also wise to choose companies and manufacturers with a long market presence, increasing the likelihood that warranties will be honoured and spare parts will remain available years from now.
You can request free quotes from vetted installers in your area through our PV Installer Directory.
Step 6: Clarify Registration and Permits
For private PV systems on residential roofs, a building permit is usually not required. However, exceptions may apply for listed buildings or special building regulations.
Regardless, the system must be properly registered after installation. This includes registration in the Market Master Data Register of the Federal Network Agency. The system must also be reported to the responsible grid operator so that grid connection and feed-in can be arranged.
Step 7: Have the Installation Carried Out Professionally
Once planning, selection, and registration are complete, installation begins. This includes mounting the substructure, attaching the modules, wiring, connecting the inverter, and — if planned — integrating a battery storage system. The system is then commissioned and technically inspected.
Self-installation is strongly discouraged. A PV system requires electrical expertise, experience with roofing work, and precise knowledge of applicable standards and safety regulations. Installation errors can not only reduce yield but also pose significant safety risks. Installation should always be carried out by a qualified specialist company.
Conclusion: Good Planning Pays Off in the Long Run
A PV system is an investment for many years. That makes it all the more important to proceed in a structured way from the start: from the roof check to proper sizing to selecting a reputable installer. Careful planning creates the foundation for a long-lasting, safe, and economical solar system.
With the PV-Energie-Planer, you can calculate your system for free — from module placement to yield calculation to profitability analysis. Give it a try.