What does the estimate mean for the recommended system?
The estimated annual savings are based on your inputs and a storage reference, not on an individual calculation for the recommended package. They cannot be used to derive a reliable payback period for that package.
Such a calculation must account for the specific system, your consumption and the total costs. Accessories, mounting, electrical work, maintenance or financing may add to the product price. The model calculation is not a yield or savings guarantee.
A specific payback period appears only when a separate, reviewed calculation with complete costs is available for the selected configuration and the estimate remains below three years. When adding storage, only the additional savings compared with the same PV system without the new storage count. The relevant assumptions are shown alongside the period. An absent payback period does not mean a system is not worthwhile.
Solar yield
PVGIS 5.3, reference location Frankfurt am Main, average of weather years 2021–2023, 14% system losses and your selected orientation and tilt.
Household consumption
Annual consumption from 1,000 to 10,000 kWh, adjustable in 100 kWh steps. For each selectable value, the dynamic H0 household profile is scaled to that annual consumption and the hourly energy balance is calculated separately. Values are not rounded to one of the previous consumption groups. The reference profile does not replace an analysis of your actual load profiles.
Electricity costs
Reference of 41 euro cents/kWh. Based on the rounded Destatis average of German household electricity prices for 2023–2025. You can adjust your actual tariff in the calculation details.
Annual savings are calculated as self-consumed solar electricity × electricity price, rounded to €5. Small differences may therefore lead to the same euro amount.
Storage effect
For each panel count from 2 to 24, hourly PVGIS values are matched against a dynamic H0 household profile via demandlib. Solar electricity is used directly first, surplus charges the storage, and stored energy is used when needed. Direct use and storage discharge share the selected output power. Solar yield before this limit remains unchanged for the same panel count.
Model assumptions, not product specifications: 2 / 4.8 / 9.6 kWh usable storage reference for 2 / 4 / 6 or more panels, a 2.4 kW charging limit, 90% round-trip efficiency and initially empty storage. No grid charging, no payment for surplus electricity and no additional storage standby consumption. The 14% PVGIS system losses are not deducted again as a flat rate. The calculation uses fixed CET without daylight-saving or regional public-holiday adjustments and averages the years 2021–2023. Short load peaks, specific device limits, shading and the actual installation are not represented. The reference does not replace product-specific planning.
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