The return on investment (ROI) shows how profitable your solar system is. In Switzerland, modern systems achieve an ROI of 150 to 250 percent over 25 years — equivalent to an annual return of around 5 to 8 percent. Photovoltaics thus beats many classic forms of investment. The fastest way to find your personal figures is the solar calculator.
The most important key figures
Two figures are decisive for profitability:
- ROI: (total return − investment) ÷ investment × 100. Example: (CHF 50,000 − CHF 20,000) ÷ CHF 20,000 = 150 percent.
- Payback period: the time until the investment is covered by returns — typically 8 to 12 years in Switzerland.
Example calculation: 10 kWp system
Starting point: 10 kWp, around 10,000 kWh annual production, 40 percent self-consumption, net investment after subsidy approx. CHF 20,900, electricity tariff 30 cents/kWh, feed-in 12 cents/kWh.
| Item | Calculation | Amount |
|---|---|---|
| Electricity cost savings | 4,000 kWh × 0.30 | CHF 1,200 |
| Feed-in remuneration | 6,000 kWh × 0.12 | CHF 720 |
| Maintenance costs | Flat rate | − CHF 200 |
| Net return per year | CHF 1,720 |
Over 25 years this amounts to around CHF 43,000 in returns, plus about CHF 6,270 in tax savings and minus around CHF 2,500 for an inverter replacement. This results in an ROI of about 220 percent and a payback in around 12 years.
Which factors influence the ROI
The return can be increased in a targeted way. The following have a positive effect:
- high self-consumption (over 50 percent)
- rising electricity prices
- optimal south orientation and little shading
- high-quality modules with a long lifespan
Negative effects come from low self-consumption, unfavourable orientation, shading, cheap modules without maintenance as well as falling feed-in remuneration.
ROI with battery storage
A storage increases the investment, but can improve the ROI with high electricity tariffs because self-consumption rises. In the example, the ROI with storage drops slightly (about 185 instead of 223 percent) and the payback extends by about a year — in return you gain independence and backup capability. Whether it pays off depends on your consumption profile.
Sensitivity: what if assumptions change?
| Scenario | ROI | Payback |
|---|---|---|
| Base scenario | approx. 223% | approx. 12 years |
| Electricity price +50% | approx. 312% | approx. 9 years |
| Self-consumption 60% | approx. 265% | approx. 10 years |
| Output −20% | approx. 158% | approx. 15 years |
Tips for optimising the ROI
- Maximise self-consumption: run large appliances during the day, charge the electric car, control the heat pump.
- Size it correctly: neither too small nor oversized.
- Quality before price: durable components pay off.
- Use subsidies: apply for all grants from the federal government, canton and municipality.
All values are example calculations for orientation. For your individual parameters use the solar calculator and then obtain firm offers via the quote comparison.
