When we bought the first PV modules in 1986, we paid around CHF 30.00 per Wp. Nowadays, the price is just CHF 0.50 per Wp.
Our Minergie house (200 m3) requires 4000 kWh per year for two persons, including an electric car that covers 10,000 km per annum. At current prices, our island system (not grid-connected) costs as follows (2021):
| PV modules 20m2/4kWp | CHF 2’000 |
| Batteries 20kWh | CHF 3’000 |
| Charger/inverter 3kW | CHF 2’000 |
| Assembly | CHF 2’000 |
| Total | CHF 9’000 |
This energy would cost CHF 1,200 p.a. from our electricity supplier, so amortisation is achieved within eight years; with a service life of fifteen years, we save CHF 9,000.
