A good annual production is not enough
The number of kWh per year does not tell you when the energy will be produced, nor how much you will keep on site, nor whether the assumptions are credible for your roof.
7 benchmarks to review
Check the surface area actually taken into account
The simulation must stick to the real usable roof, not to an ideal surface without obstacles.
Look at the monthly distribution
Swiss seasonality matters a lot. A serious estimate should show winter, mid-season and summer.
Control shading assumptions
Chimneys, trees, relief and neighboring buildings can significantly change the result.
Distinguish between production and self-consumption
Producing a lot and consuming usefully on site are two different things.
Look at what is assumed for network injection
The surplus recovery rate must remain prudent. The injection should not be treated as a generous pension.
Integrate future uses of the building
A simulation fixed on current consumption can underestimate the logic of a future project.
Always return to the comparative scenario
The best simulation is the one that helps compare realistic variants, not the one that flatters the most.