Solar Payback Calculator
Estimate annual generation, self-consumption value, export value and simple payback for a residential solar system.
Currency selection changes the unit label, not an exchange rate. Enter every price in the selected currency.
How to choose the inputs
Use a yield estimate for your location and roof, not a country-wide promise. Self-consumption means the share of annual PV generation used on site, not the share of household demand covered. Export value must match the marginal value under your own contract.
Formula and measurement boundary
Three worked scenarios
These are fixed hypothetical examples, not live tariffs or verified product data. They use EUR and kilometres where applicable and do not change with the form settings. Only the table input changes.
Unchanged inputs
- System size: 6 kWp
- Annual specific yield: 1,000 kWh/kWp
- Electricity price: 0.25 EUR/kWh
- Export value: 0.05 EUR/kWh
- Installed cost: 6,000 EUR
| Self-consumption | Estimated result |
|---|---|
| 30 % | 9.1 years |
| 50 % | 6.7 years |
| 70 % | 5.3 years |
Annual generation stays at 6,000 kWh. Increasing self-consumption raises annual gross value from €660 to €900 and €1,140 under these assumed tariffs. The tool divides investment by that value; it does not calculate an investment return rate.
What this result does not establish
- Maintenance, financing, degradation, replacement and discounting are excluded.
- Net-metering, storage-service fees and tariff tiers cannot be modelled exactly with one export price.
- Ten-year value is ten identical years before additional costs, not net profit. Zero annual value gives no finite payback.
Self-consumption and exported electricity have different values
The following are additional hypothetical decision examples. Separately discussed fees, reserve allowances or running costs are not automatically added to the form result.
An illustrative system producing 7,000 kWh/year with 40% direct self-consumption avoids buying 2,800 kWh. At €0.25/kWh that is €700. The remaining 4,200 kWh exported at €0.06/kWh adds €252. Subtract €100/year running costs: the annual benefit is €852. A €7,000 net installation cost gives 8.22 years simple payback. These are assumptions, not a forecast for a particular roof or country.
At 70% direct self-consumption with the same production, tariffs and costs, annual benefit becomes €1,251 and simple payback 5.60 years. The extra €399 is the value of shifting 2,100 kWh from export to direct use. It is not an extra 2,100 kWh of generation. A battery used to shift that energy has its own cost, losses and capacity limits.
Use production from a site-specific assessment and keep import/export settlement rules consistent with the contract. Annual production cannot tell you whether daytime output overlaps your demand. Simple payback omits discounting, degradation, financing, replacements and tariff changes. Obtain a cash-flow estimate before treating this result as an investment return.
Sources and their scope
- European Commission JRC: PVGIS — Location-specific PV estimates; not a tariff or payback guarantee.
These reference pages were accessed on 21 September 2026. The equations and examples are the site’s own model; these sources do not certify its defaults or results.
Frequently asked questions
Can I enter a grant?
For a simple scenario, subtract only a confirmed grant from installed cost. Do not assume eligibility or future awards.
Does a short result guarantee a good investment?
No. It describes this simplified set of inputs, not future tariffs, equipment life or cash flow.
Read the model and verification limits