Solar Panel ROI Calculator – Slovenia 2026
A 6.5 kWp system without a battery pays back in Slovenia in 8.63 years: the annual saving is €825, self-generated electricity costs €0.04/kWh (81% cheaper than the €0.21/kWh grid price), and over the 25-year system lifetime you save €26,454. Enter your own solar system's parameters or use the simple wizard to find out the annual savings, payback period and electricity production in Slovenia.
Basic
Rough conversion of your bill to annual consumption using the average electricity price — estimate only.
Recommended size for your consumption: 6.5 kWp.
Estimate based on an average price of ~€1,050/kWp (materials, installation, VAT) — the actual price depends on the installer, roof and chosen components.
Your result
8.63 years
Payback period
Calculated for system: 6.5 kWp · no battery
Annual savings
€825
Monthly bill before → Monthly bill after
€105 → €58
Cost of your own kWh
€0.04
grid price: €0.21
Lifetime savings
€26,454
What this means: Your own electricity works out at €0.04/kWh, which is 81% cheaper than the grid price of €0.21/kWh. The system covers roughly 45% of your annual electricity use; you'll still buy the rest from the grid.
| Setup 1 | |
|---|---|
| Calculated for system | 6.5 kWp · no battery |
| System cost | €7,650 |
| Payback period | 8.63 years |
| Annual savings | €825 |
| Lifetime savings | €26,454 |
| Annual production | 7475 kWh |
| CO₂ saved | 1.45 t/year |
| Self-consumption | 36.12 % |
| Annual electricity consumption | 6000 kWh |
Setup 1
- Self-consumption: 2700 kWh (36 %)
- Exported to grid: 4775 kWh (64 %)
This calculation is indicative and is based on the entered inputs and average values for Slovenia (specific yield, electricity prices, the current market surplus price rather than exact monthly/hourly fluctuations). Actual production and savings depend on the specific roof, orientation, shading and installer. It does not replace a quote from a solar installer.
How solar panel ROI is calculated
Annual production is calculated as the installed capacity (kWp) multiplied by the specific yield (kWh produced per year per 1 kWp) for the given location in Slovenia. Part of the electricity produced is used directly by the household (self-consumption), while the rest is exported to the grid at the current market surplus price.
Annual savings are the sum of two parts: money saved on electricity that would otherwise have been bought (self-consumption × electricity price), and income from surplus exported to the grid (remaining production × feed-in price).
The payback period is the year in which cumulative savings exceed the net investment (system and any battery price, minus the subsidy). The calculator also accounts for the annual rise in electricity prices and the gradual degradation of panel output.
The calculator lets you compare 2–3 setups side by side, for example a system without a battery and one with a battery, and immediately see the difference in payback period and total savings.
Frequently asked questions
How many years does it take a 6.5 kWp solar system to pay back in Slovenia?
For a 6.5 kWp system without a battery and an annual household consumption of 6,000 kWh, the payback period is 8.63 years. The annual saving is €825 and the monthly electricity bill drops from €105 to €58.
How much do I save with a 6.5 kWp solar system in Slovenia per year?
For the default 6.5 kWp system without a battery, the annual saving is €825, and €26,454 over the full 25-year system lifetime.
How much does self-generated kWh cost compared to the grid in Slovenia?
Self-generated electricity costs around €0.04/kWh, which is 81% cheaper than the €0.21/kWh bought from the grid (2026 prices).
How is the annual solar production calculated?
Multiply the system size in kWp by the location's specific yield in kWh/kWp/year. In Slovenia, the typical figure is around 1150 kWh/kWp/year, higher along the coast and in the lowlands, lower in the alpine regions in the northwest.
What does self-consumption mean and why does it matter?
It's the share of produced electricity you use directly instead of exporting it to the grid. Higher self-consumption means a considerably faster payback, because purchased electricity is much more expensive than the surplus feed-in price.
Is battery storage worth it?
Especially in Slovenia – a battery increases self-consumption and therefore savings, but also increases the investment. Compare the setup with and without a battery in the calculator.
Why is the surplus feed-in price so low in Slovenia?
Slovenia has abolished annual net-metering of surplus electricity. Surplus power is now bought on an ongoing basis at the current market price, which is significantly below the retail electricity price. This makes self-consumption and battery storage economically much more attractive than in countries that still use net-metering.
Why does production decrease over time?
Solar panels gradually lose a small amount of output over time (degradation, typically around 0.5% per year). The calculator accounts for this in the production and savings estimate over the system's full lifetime.
How much CO₂ does a home solar system save?
It depends on annual production and the emissions factor of the Slovenian electricity grid, which is lower than Slovakia's, Czechia's, Hungary's and Germany's thanks to a high share of nuclear power, though slightly higher than Austria's thanks to its high hydropower share. The calculator converts the electricity produced into tonnes of CO₂ saved per year based on the current energy mix.
Related tools
Last updated: 24 July 2026